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  [Transcriber’s Note:

  Two other papers from ASCE _Transactions_ LXVIII (September 1910) are
  referenced in this paper:

    No. 1150, “The New York Tunnel Extension...” by Charles W. Raymond,
    available from Project Gutenberg as e-text #18229.

    No. 1151, “The North River Division” by Charles M. Jacobs, e-text
    #18548, generally cited as “the paper by Mr. Jacobs”.

  The word “Figure” is used in two ways. It refers either to individual
  numbered Figures (1-21), or to any of the four pictures that make up
  each Plate, identified in the form “Fig. 2, Plate XXI”. Figures 1-4
  are always discussed as a group.

  Single letters in boldface are shown as =A=. Typographical errors are
  listed at the end of the text.]

       *       *       *       *       *
           *       *       *       *
       *       *       *       *       *

  American Society of Civil Engineers
  Instituted 1852
  TRANSACTIONS

  Paper No. 1154

  THE NEW YORK TUNNEL EXTENSION OF THE PENNSYLVANIA RAILROAD.
  THE BERGEN HILL TUNNELS.[1]

  By F. LAVIS, M. Am. Soc. C. E.

    [Footnote 1: Presented at the meeting of April 6th, 1910.]


_Location._--That section of the Pennsylvania Railroad’s New York
Tunnels lying west of the Hudson River is designated Section “K,” and
the tunnels are generally spoken of as the Bergen Hill Tunnels. Bergen
Hill is a trap dike (diabase) forming the lower extension of the Hudson
River Palisades.

There are two parallel single-track tunnels, cross-sections of which are
shown on Plate VIII of the paper by Charles M. Jacobs, M. Am. Soc. C. E.
The center line is a tangent, and nearly on the line of 32d Street, New
York City, produced, its course being N. 50° 30' W. The elevation of the
top of the rail at the Weehawken Shaft (a view of which is shown by
Fig. 2, Plate XXII), on the west bank of the Hudson River, is about 64
ft. below mean high water; and at the Western Portal, or Hackensack end,
the rail is about 17 ft. above; the grade throughout is 1.3%, ascending
from east to west. The length of each tunnel between the portals is
5,920 ft.

A general plan and profile of these tunnels is shown on Plate I of the
paper by Charles W. Raymond, M. Am. Soc. C. E. At Central Avenue a shaft
212 ft. deep was sunk. It is 3,620 ft. from the Weehawken Shaft.

  [Illustration: Plate XXI.
  Fig. 1: K 94. P.R.R. Tunnels, N. R. D. Section K. (Bergen Hill
  Tunnels.) from Hackensack Poral, North Cut and Cover Section, and
  Portal looking East from Sta. 323. Dec. 8, 05.
  Fig. 2: K 71. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels) Method of using Cross-Section Rod in getting Sections of
  Tunnel. Aug. 30, 06.
  Fig. 3: K 115. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels) Weehawken Shaft, North Tunnel Conveyor used by King Rice
  and Garney for handling and placing concrete. June 3, 07.
  Fig. 4: K 116. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels) Weehawken Shaft, North Tunnel. View of conveyor for placing
  concrete, with bucket suspended over hopper above belt. Steel forms
  in fore ground. June 4, 07.]


_History._--The contract for this work was let on March 6th, 1905, to
the John Shields Construction Company; it was abandoned by the Receiver
for that company on January 20th, 1906, and on March 20th, of that year,
was re-let to William Bradley, who completed the work by December 31st,
1908.

The progress of excavation and lining in the North Tunnel is shown
graphically on the progress diagram, Fig. 9, that of the South Tunnel
being practically the same.


_Geology._--Starting west from the Weehawken Shaft, the tunnels pass
through a wide fault for a distance of nearly 400 ft., this fault being
a continuation of that which forms the valley between the detached mass
of trap and sandstone known as King’s Bluff, which lies north of the
tunnels, and the main trap ridge of Bergen Hill.

The broken ground of the fault, which consists of decomposed sandstone,
shale, feldspar, calcite, etc., interspersed with masses of harder
sandstone and baked shale, gradually merges into a compact granular
sandstone, which, at a distance of 460 ft. from the shaft, was
self-supporting, and did not require timbering, which, of course, had
been necessary up to this point.

A full face of sandstone continued to Station 274 + 60, 940 ft. from the
shaft, where the main overlying body of trap appeared in the heading.
The full face of the tunnel was wholly in trap at about Station 275 +
30, and continued in this through to the Western Portal, where the top
of the trap was slightly below the roof of the tunnel, with hardpan
above. The contact between the sandstone and the overlying trap was very
clearly defined, the angle of dip being approximately 17° 40' toward the
northwest.

The sandstone and trap are of the Triassic Period, and the trap of this
vicinity is more particularly classified as diabase.

The character of the trap rock varied considerably. At the contact,
at Station 275, and for a distance of approximately 200 ft. west,
corresponding to a thickness of about 60 ft. measured at right angles to
the line of the contact, a very hard, fine-grained trap, almost black in
color, was found, having a specific gravity of 2.98, and weighing 186
lb. per cu. ft. The hardness of this rock is attested by the fact that
the average time required to drill a 10-ft. hole in the heading, with a
No. 34 slugger drill, with air at 90 lb. pressure, was almost 10 hours.
The specific gravity of this rock is not as high as that of some other
specimens of trap tested, which were much more easily drilled. This rock
was very blocky, causing the drills to bind and stick badly, and, when
being shoveled back from the heading, as it fell it sounded very much as
though it were broken glass.

The remainder of the trap varied from this, through several changes of
texture and color, due to different amounts of quartz and feldspar, to a
very coarse-grained rock, closely resembling granite of a light color,
though quite hard. The speed of drilling the normal trap in the heading
was approximately 20 to 25 min. per ft., as compared with the 60 min.
per ft. noted above, the larger amounts of quartz and feldspar
accounting for the greater brittleness and consequently the easier
drilling qualities of the rock. The normal trap in these tunnels has a
specific gravity varying from 2.85 to 3.04, and weighs from 179 to 190
lb. per cu. ft.

The temperature of the tunnels, at points 1,000 ft. from the portals at
both ends, remained nearly stationary, and approximately between 50° in
winter and 60° in summer, up to the time the headings were holed
through, being practically unaffected by daily changes in the
temperature outside. At the western end, after the connection with the
Central Shaft headings was made, there was almost always a current of
air from the portal to the shaft, and ascending through the latter. This
tended to make the temperature in this part of the tunnel correspond
more nearly with the outside temperature; in fact, the variation was
seldom more than 5° Fahr.


_Timbering._--These tunnels have been excavated entirely by the center
top heading method, almost invariably used in the United States.
Timbering, where required, was of the usual segmental form with outside
lagging, as shown in several of the photographs. In a few places it was
necessary to hold the ground as the work progressed, and, in such cases,
crown bars were used in the headings.

There was some little trouble at the Western Portal, where the top of
the rock was very near the roof of the tunnel, as shown by Fig. 1, Plate
XXI. A side heading was driven at the level of the springing line until
a point was reached where the roof was self-supporting, and the
timbering was brought out to the face of the portal from that point.

  [Illustration: Plate XXII.
  Fig. 1: K 26. P.R.R. Tunnels, N. R. D. Sect. K. (Bergen Hill
  Tunnels,) Weehawken Shaft. Scaffold car in South Tunnel at Sta.
  267+60. Jan. 11, 06.
  Fig. 2: K 31. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels) Weehawken Shaft. Headhouse at ? elevator frame work,
  looking West. Oct. 17, 06.
  Fig. 3.--Round Holes in Concrete Forms.
  Fig. 4.--Round Holes in Concrete Forms Completed.]


_Drilling._--Where no timbering was required, several different methods
were used in drilling and excavating the solid rock, though in all cases
a center top heading was driven. The four diagrams, Figs. 1, 2, 3,
and 4, give typical examples of these methods and show, in the order of
their numbers, the general tendency of the development from a small
heading kept some distance ahead of the bench, to a large heading with
the bench kept close to it. The notes on each diagram give the general
details of the quantity of drilling and powder used, methods of
blasting, etc., and on the progress profile, Fig. 6, is indicated those
portions of the tunnels in which each method was used.

All the drills used throughout the work by Mr. Bradley were Rand No. 34
sluggers, with 3⅝-in. cylinders, and the steel was that known as the
“Black Diamond Brand,” 1⅜-in., octagon. It was used in 2, 4, 6, 8, 10,
and 12-ft. lengths; toward the end of the work it was proposed to use
14-ft. lengths, but owing to some delay in delivery this length was
never obtained. The starters, 18 to 24 in. long, were sharpened to 2¾ to
3-in. gauge, which was generally held up to depths of 6 ft.; then the
gauge gradually decreased until it was 1¾ to 2¼ in. at the bottom of a
12-ft. hole. Frequently, as many as three or four starters were used in
starting a hole, and generally two sharpenings were required for each
2 ft. drilled, after the first 6 ft. It is estimated that about ¼ in. of
steel was used for each sharpening, and that there was an average of one
sharpening for every foot drilled.

The total quantity of steel used up, lost, or scrapped on the whole work
was almost exactly 1 ft. for each 10 cu. yd. excavated, equal to 1¼ in.
of steel per yard, distributed approximately as follows:

  Sharpening      ¾ to ⅞ in.
  Other losses    ½ to ⅜  ”
                 ---------------
  Total         1¼ in. per cu. yd.

An “Ajax” drill sharpener was used, and proved very satisfactory. Rubber
and cotton hose, covered with woven marlin, was used for the bench
(3 in. inside diameter, in 50-ft. lengths), for drills (1 in. in
diameter, in 25-ft. lengths), and for steam shovels (2½ in. in diameter,
in 50-ft. lengths). Hose coverings of wound marlin, and of woven marlin
with spiral steel wire covering were tried, but were not satisfactory,
owing to the unwinding of the marlin and the bending of the steel
covering.

  [Illustration: Fig. 1. {Drilling Method No. 1}
  CROSS-SECTION, LONGITUDINAL SECTION, PLAN]

  Drilling Method No. 1: Small heading, 60 to 80 ft. long. Two columns
    used in heading, with two drills on each. Drills on sub-bench and
    main bench mounted on tripods.

  +--------------------------------------------------+
  |                    Per Round                     |
  +---------+---------+---------+----------+---------+
  |         |  Total  | No. of  |  Pounds  |         |
  |         |  Depth  | Cubic   |    of    | Advance |
  |         | Drilled | Yards   | Dynamite |         |
  +---------+---------+---------+----------+---------+
  | Heading | 140-155 | 18-21.6 |  93-131  |   5-6   |
  +---------+---------+---------+----------+---------+
  | Bench   | 110-120 | 53-60   |  76-97   |  3½-4   |
  +---------+---------+---------+----------+---------+

  +---------+--------------------+-----------------------------+
  |         |   Per Cubic Yard   |  Per linear Foot of Tunnel  |
  |         +---------+----------+-------+---------+-----------+
  |         | Linear  |  Pounds  | Cubic | No. of  |  Pounds   |
  |         |  Feet   |    of    | Yards |  Feet   |   of      |
  |         | Drilled | Dynamite |       | Drilled | Dynamite  |
  +---------+---------+----------+-------+---------+-----------+
  | Heading |   8-9   |    5-6   |  3.6  | 29.-32  |   18-22   |
  +---------+---------+----------+-------+---------+-----------+
  |  Bench  |     2   |  1.4-1.6 | 15.4  | 30.-31  | 21.5-24.6 |
  +---------+---------+----------+-------+---------+-----------+
  |                       Total  | 19    | 59.63   | 39.5-46.6 |
  +------------------------------+-------+---------+-----------+
  | Per cubic yard, whole tunnel section | 3 to 33 |  2.1-2.5  |
  +--------------------------------------+---------+-----------+

  +---------------------------------------------------+------------+
  |                                                   |  Number    |
  |           Blasting Notes:                         | of Sticks  |
  |                                                   +------------+
  | Heading: First Round: 6 sticks, 60% in each cut   |            |
  |            hole, cut generally blasted twice      |  36 to  72 |
  |          Second Round: 3 side holes each side,    |            |
  |            5 sticks, 40% ea.                      |     30     |
  |          Third Round: Rest of side holes and dry  |            |
  |            holes, 5 sticks, 40% each              |     40     |
  |          Stub holes, say                          |   5 to  15 |
  |                                                   +------------+
  |                                   Total Sticks    | 111 to 157 |
  |                                                   +------------+
  |                                   Total Pounds    |  93 to 131 |
  |                                                   +------------+
  | Sub-bench: 4 widening holes; 2 to 3 sticks,       |            |
  |              each, 40%                            |  10 to  12 |
  |            6 down holes; 5 to 7 sticks, each, 40% |  30 to  42 |
  | Bench: 6 holes; 6 to 8 sticks each, 40%           |  36 to  48 |
  |        Taking up bottom, average, say             |     15     |
  |                                                   +------------+
  |                                   Total Sticks    |  91 to 117 |
  |                                                   +------------+
  |                                   Total Pounds    |  76 to  97 |
  +---------------------------------------------------+------------+


  [Illustration: Fig. 2.
  CROSS-SECTION, LONGITUDINAL SECTION, PLAN]

  Drilling Method, No. 2: Five drills in heading, mounted on three
    columns; the holes marked with a cross (X) were drilled with the
    drills on the center column.

  +--------------------------------------------------+
  |                    Per Round                     |
  +---------+---------+---------+----------+---------+
  |         |  Total  | No. of  |  Pounds  |         |
  |         |  Depth  | Cubic   |    of    | Advance |
  |         | Drilled | Yards   | Dynamite |         |
  +---------+---------+---------+----------+---------+
  | Heading | 190-220 | 35-42   | 134-196  | 6½-8    |
  +---------+---------+---------+----------+---------+
  | Bench   | 110-130 |   55    |  79-106  |    4    |
  +---------+---------+---------+----------+---------+

  +---------+--------------------+-----------------------------+
  |         |   Per Cubic Yard   |  Per linear Foot of Tunnel  |
  |         +---------+----------+-------+---------+-----------+
  |         | Linear  |  Pounds  | Cubic | No. of  |  Pounds   |
  |         |  Feet   |    of    | Yards |  Feet   |   of      |
  |         | Drilled | Dynamite |       | Drilled | Dynamite  |
  +---------+---------+----------+-------+---------+-----------+
  | Heading | 5.4-6.0 |  3.9-5.0 |  5.3  |28 to 32.| 20.7-26.5 |
  +---------+---------+----------+-------+---------+-----------+
  | Bench   |  2.-2.4 |  1.4-2.0 | 13.7  | 27.-33. | 19.2-27.4 |
  +---------+---------+----------+-------+---------+-----------+
  |                       Total  |  19   | 55.-65. | 39.9-53.9 |
  +------------------------------+-------+---------+-----------+
  | Per cubic yard, whole tunnel section | 2.9-3.4 |  2.1-2.8  |
  +--------------------------------------+---------+-----------+


  +---------------------------------------------------+------------+
  |                                                   |  Number    |
  |           Blasting Notes:                         | of Sticks  |
  |                                                   +------------+
  | Heading: First Round; 2 to 3 relieving holes      |            |
  |            sprung with 4 to 5 sticks each         |   8 to  15 |
  |          8 cut holes, 7 sticks each               |            |
  |            (sometimes shot twice)                 |  56 to 112 |
  |          First side round, 6 holes, 6 sticks      |            |
  |            each                                   |       36   |
  |          Widening and dry holes, 10 to 12,        |            |
  |            6 sticks each                          |  60 to  72 |
  |                                                   +------------+
  |                                   Total Sticks    | 160 to 235 |
  |                                                   +------------+
  |                                   Total Pounds    | 134 to 196 |
  |                                   ----------------+------------+
  | Sub-bench: 8 holes, 4 to 6 sticks, each           |  32 to  48 |
  |                                                   |            |
  | Bench: 8 holes, 6 to 8 sticks, each               |  46 to  64 |
  |        Taking up bottom, average                  |     15     |
  |                                                   +------------+
  |                                   Total Sticks    |  95 to 127 |
  |                                                   +------------+
  |                                   Total Pounds    |  79 to 109 |
  +---------------------------------------------------+------------+



  [Illustration: Fig. 3.
  CROSS-SECTION, LONGITUDINAL SECTION, PLAN]

  Drilling Method No. 3: Heading same as second method, but larger lift
    taken off bench, and lift holes drilled in bottom bench in order to
    get down to grade in floor. Bench kept closer to heading.

  +---------------------------------------------------------+
  |                       Per Round                         |
  +---------+------------+-----------+------------+---------+
  |         |   Total    |  No. of   |   Pounds   |         |
  |         |   Depth    |  Cubic    |     of     | Advance |
  |         |  Drilled   |  Yards    |  Dynamite  |         |
  +---------+------------+-----------+------------+---------+
  | Heading | 190 to 220 | 35 to 42  | 134 to 196 | 6½ to 8 |
  +---------+------------+-----------+------------+---------+
  |         |            |           |            |         |
  | Bench   | 145  ” 190 | 90 to 110 | 118  ” 167 | 6½  ” 8 |
  +---------+------------+-----------+------------+---------+

  +-----+-------------------------+----------------------------------+
  |     |     Per Cubic Yard      |    Per linear Foot of Tunnel     |
  |     +------------+------------+-------+-----------+--------------+
  |     |  Linear    |   Pounds   | Cubic |  No. of   |   Pounds     |
  |     |   Feet     |     of     | Yards |   Feet    |    of        |
  |     |  Drilled   |  Dynamite  |       |  Drilled  |  Dynamite    |
  +-----+------------+------------+-------+-----------+--------------+
  | Hd. | 5.4 to 6.0 | 3.9 to 5.0 |  5.3  |  28 to 32 | 20.7 to 26.5 |
  +-----+------------+------------+-------+-----------+--------------+
  | B.  | 1.6  ” 1.9 | 1.3  ” 1.8 | 13.7  |  22  ” 36 | 17.8  ” 24.7 |
  +-----+------------+------------+-------+-----------+--------------+
  |                        Total  | 19    |  50  ” 58 | 38.5  ” 51.2 |
  +-------------------------------+-------+-----------+--------------+
  | Per cubic yard, whole tunnel section  | 2.6 ” 3.1 |  2.0  ”  2.6 |
  +---------------------------------------+-----------+--------------+

  +---------------------------------------------------+------------+
  |                                                   |  Number    |
  |           Blasting Notes:                         | of Sticks  |
  |                                                   +------------+
  | Heading: First Round: 2 to 3 relieving holes      |            |
  |            sprung, with 4 to 5 sticks each        |   8 to  15 |
  |          8 cut holes, 7 sticks each               |            |
  |            (sometimes shot twice)                 |  56 to 112 |
  |          First side round, 6 holes, 6 sticks      |            |
  |            each                                   |    36      |
  |          Widening and dry holes, 10 to 12 holes,  |            |
  |            6 sticks each                          |  60 to  72 |
  +---------------------------------------------------+------------+
  |                                   Total Sticks    | 160 to 235 |
  +---------------------------------------------------+------------+
  |                                   Total Pounds    | 134 to 196 |
  +---------------------------------------------------+------------+
  |                                                   |            |
  | Sub-bench: 4 widening holes, 4 to 5 sticks each,  |            |
  |              2 rounds                             |  32 to  40 |
  |            6 down holes, 5 to 7 sticks each,      |            |
  |              2 rounds                             |  60 to  84 |
  |                                                   |            |
  | Bench: 4 down holes, 5 to 7 sticks each           |  20 to  28 |
  |        6 to 8 lift holes, 5 to 6 sticks each      |  30 to  48 |
  +---------------------------------------------------+------------+
  |                                   Total Sticks    | 142 to 200 |
  +---------------------------------------------------+------------+
  |                                   Total Pounds    | 118 to 167 |
  +---------------------------------------------------+------------+


  [Illustration: Fig. 4.
  CROSS-SECTION, LONGITUDINAL SECTION, PLAN]

  Drilling Method No. 4: 8 drills on 4 columns used in heading. Bench
    taken off in one lift. Bottom taken up with lift holes.

  +--------------------------------------------------+
  |                    Per Round                     |
  +---------+---------+---------+----------+---------+
  |         |  Total  | No. of  |  Pounds  |         |
  |         |  Depth  | Cubic   |    of    | Advance |
  |         | Drilled | Yards   | Dynamite |         |
  +---------+---------+---------+----------+---------+
  | Heading | 310-320 |  63-71  | 215-257  |   8-9   |
  +---------+---------+---------+----------+---------+
  | Bench   | 190-210 | 89-100  | 107-155  |   8-9   |
  +---------+---------+---------+----------+---------+

  +---------+--------------------+------------------------------+
  |         |   Per Cubic Yard   |  Per linear Foot of Tunnel   |
  |         +---------+----------+-------+----------+-----------+
  |         | Linear  |  Pounds  | Cubic | No. of   |  Pounds   |
  |         |  Feet   |    of    | Yards |  Feet    |   of      |
  |         | Drilled | Dynamite |       | Drilled  | Dynamite  |
  +---------+---------+----------+-------+----------+-----------+
  | Heading | 4.5-5.1 | 3.4-5.7  |  7.9  | 35.6-45. | 26.9-45.0 |
  +---------+---------+----------+-------+----------+-----------+
  | Bench   | 1.9-2.2 | 1.2-1.7  | 11.1  | 21.1-24. | 13.3-18.9 |
  +---------+---------+----------+-------+----------+-----------+
  |                       Total  | 19    | 56.7-69. | 40.2-63.9 |
  +------------------------------+-------+----------+-----------+
  | Per cubic yard, whole tunnel section |   3.-3.6 |  2.1-3.4  |
  +--------------------------------------+----------+-----------+

  +---------------------------------------------------+------------+
  |                                                   |  Number    |
  |           Blasting Notes:                         | of Sticks  |
  |                                                   |            |
  | All holes of whole round are cleaned and loaded   |            |
  |   before blasting is started                      |            |
  |                                                   |            |
  | First Round: 5-6 lift holes, 7 to 9 sticks each   |  35 to  54 |
  |     First row, sub-bench, 6 holes, 6 to 8         |            |
  |         sticks each                               |  36 to  48 |
  |                                                   |            |
  | Second Round: Second row, sub-bench and widening  |            |
  |         holes, 8 to 10 holes, 6 to 8 sticks each  |  48 to  64 |
  |     Stub holes                                    |  10 to  20 |
  |                                                   |            |
  |                            Bench: Total Sticks    | 129 to 186 |
  |                                   Total Pounds    | 107 to 155 |
  |                                                   |            |
  | Third Round: 8 cut holes, 7 sticks each, often    |            |
  |         requires 3 to 4 charges                   | 112 to 224 |
  | Fourth Round: 8 holes, First side round, 5 to 7   |            |
  |         sticks each                               |  40 to  56 |
  | Fifth Round: 8 holes, Second side round, 5 to 7   |            |
  |         sticks each                               |  40 to  56 |
  |     2 dry holes 5 to 7 sticks each                |  10 to  14 |
  | Sixth Round: 4 to 6 widening holes and dry holes, |            |
  |         6 sticks each                             |  36 to  48 |
  |     Stub holes                                    |  20 to  30 |
  |                                                   |            |
  |                          Heading: Total Sticks    | 258 to 428 |
  |                                   Total Pounds    | 215 to 357 |
  +---------------------------------------------------+------------+


The average quantity of powder used on the whole work was about 2.9 lb.
per cu. yd. The tables on the diagrams, Figs. 1, 2, 3, and 4, show that
the quantity actually used in making the advance at the main working
faces was about 2.5 lb. The difference is accounted for by the larger
percentage of powder used for trimming the sides, breaking out the
cross-passages between the tunnels, and the excavation of the ditches,
the latter operation not being done until the concrete lining was about
to be put in.

There was some time, too, during the earlier stages of the work, when it
is believed that an excessive quantity of powder was used; for one or
two months it ran up to 4 lb. per cu. yd.

  [Illustration: Fig. 5.
  MUCK CAR USED AT WEEHAWKEN SHAFT]

The dynamite used was “Forcite.” At first, both 40% and 60% were used,
the 60% generally only for blasting the cut in the headings; during the
latter part of the work, however, the 60% was used exclusively.

The rock as a rule broke very well, and only a comparatively small
quantity could not be handled by the shovels without being broken up
further by block-holing. In the sandstone the quantity of powder per
cubic yard was much more than for any of the trap.

In drilling the Central Shaft, a 6-hole cut was made approximately on
the center line, east and west, the enlargement requiring about 18 more
holes, which were generally about 6 ft. deep, the average advance being
about 4 ft. per day of 24 hours.

  [Illustration: Fig. 6.
  PROGRESS PROFILES OF NORTH AND SOUTH TUNNELS SHOWING MONTHLY
  EXCAVATION]

The drills were run by steam until a depth of about 150 ft. had been
reached, air from the plant at Hackensack being available after that
time. Four drills were used most of the time, and six later when air was
available. This work was done entirely by the John Shields Construction
Company, and a depth of 205 ft. was sunk in 6 months (from July 15th,
1905, to January 15th, 1906). A derrick was used for hoisting and
lowering men and tools during the sinking, elevators being put in later.


  [Illustration:
  PLATE XXIII.]

_Drilling Data._--During the progress of the work, both general and
detailed observations were made of the drilling, the results of which
are shown in the tables. Table 1 has been compiled from the records as
platted daily on the chart from the inspectors’ reports, as shown by
Plate XXIII, and described on page 113. Table 2 contains some data
relating to the drilling in the headings.

The general results of these observations show that the average time the
drills were “actually working” was 5.2 hours per shift, and that they
were actually “hitting the rock” about half of this time, or about 2.5
hours per shift. The average depth drilled per hour, during the time the
drills were “actually working,” was 2.66 ft.

The “actual working time,” as noted above, covers the period from the
time the drills were first set up in the heading after blasting until
they were taken down for the next blast; it does not include the time
occupied in setting up or taking down, which would probably average 30
min. more per shift. It is believed that this figure will also apply
very closely to drills working on the bench, though no actual
observations were taken to determine this, on account of the
irregularity with which they were worked.

The actual working time of the drills in the 736 shifts (7,360 hours)
covered by Table 1, was 3,826 hours, or 5.2 hours per shift. The average
depth drilled per yard, as shown in the last column of Table 1, agrees
fairly well with the figures on the diagrams, Figs. 1, 2, 3, and 4.

Table 2 has been compiled from detailed timed observations of individual
drilling of down holes in the bench, for periods of 7 or 8 hours each,
in January, 1907. The work at that time was in fairly normal condition
at all points.

The figures in the third column of Table 2 include the time required for
moving from one hole to another, when this occurred during the
observation, the time required for changing bits, oiling drills, etc.,
and all delays of all kinds. A close record of the delays was kept, and
it was considered that, of the 93 hours, 48 min., in Table 2, the
unnecessary delays amounted to 5 hours, 7 min., or about 5½ per cent.

  TABLE 1.

  #S. Number of shifts covered by observations.
  #Hrs Average number of hours worked per shift.
  D/Hr Average depth drilled per hour per drill.
  D/Yd Average depth drilled per yard.
  Hack. Hackensack
  Whk. Weehawken
  CS Central Shaft

  ----------------+-----------+----+-----------+------+------+------
      Method.     |   Date.   | #S | Place.    | #Hrs | D/Hr | D/Yd
  ----------------+-----------+----+-----------+------+------+------
                 {| Aug.  ’06 | 44 | Hack., N. | 5.69 | 2.78 | 10.1
                 {| Sept. ’06 | 38 |   ”    N. | 5.80 | 3.77 | 11.1
  No. 1--        {| Aug.  ’06 | 43 |   ”    S. | 5.60 | 2.89 |  9.1
      4-drill    {| Sept. ’06 | 36 |   ”    S. | 6.18 | 2.65 |  8.7
                 {| Jan.  ’07 | 16 | CS E.  N. | 5.99 | 2.99 |  8.2
                 {| Jan.  ’07 | 20 |   ”    S. | 6.05 | 2.9  |  7.1
                 {| Apr.  ’07 | 48 | CS W.  N. | 4.92 | 3.3  |  6.7
                 {| Apr.  ’07 | 48 |   ”    S. | 5.00 | 3.2  |  7.7
                  |           |    |           |      |      |
                 {| Dec.  ’06 | 54 | Whk.,  N. | 4.95 | 2.16 |  4.52
  Nos. 2 and 3-- {| Dec.  ’06 | 54 |   ”    S. | 5.23 | 2.14 |  4.54
      5-drill    {| Dec.  ’06 | 52 | Hack., N. | 5.03 | 2.2  |  5.77
                 {| Dec.  ’06 | 54 |   ”    S. | 5.90 | 1.82 |  5.67
                  |           |    |           |      |      |
  No. 4--        {| June  ’07 | 56 | Whk.,  N. | 4.77 | 2.55 |  4.23
      7-drill    {| June  ’07 | 58 |   ”    S. | 4.82 | 2.26 |  3.88
                  |           |    |           |      |      |
      8-drill    {| May   ’07 | 60 | Hack., N. | 4.67 | 2.44 |  5.00
                 {| May   ’07 | 60 |   ”    S. | 4.54 | 2.57 |  4.80
  ----------------+-----------+----+-----------+------+------+------


  TABLE 2.

  Hrs. _Hours._
  Min. _Minutes._

  ----------------+----------+---------------+----------------
        Date.     |  Place.  |     Total     | Number of feet
                  |          | working time. |    drilled.
  ----------------+----------+---------------+----------------
                  |          |  Hrs.   Min.  |
  Jan. 14th, 1907 | Whk.  N. |   8      0    |      15
   ”   15th, 1907 |   ”   N. |   7     32    |      12
                  |   ”   N. |   7     22    |      14
   ”   12th, 1907 |   ”   S. |   8      0    |      20
                  |   ”   S. |   8      0    |      11
                  |   ”   S. |   8      0    |      10
   ”   11th, 1907 | Hack. N. |   8      0    |      13
   ”   17th, 1907 |   ”   N. |   7     10    |      10
                  |   ”   N. |   7      5    |      11
                  |   ”   N. |   7     10    |      10
   ”   16th, 1907 |   ”   S. |   4     20    |      10
                  |   ”   S. |   6      9    |      10
                  |   ”   S. |   7     ...   |       8
  ----------------+----------+---------------+---------------
       Totals.    |          |  93     48    |     154
  ----------------+----------+---------------+---------------
  Average: 36.6 min. per ft. drilled, or 1.64 ft. drilled per hour.

As a check on the average figures obtained from various sources, the
following estimate of the cost of drilling per cubic yard was made up
from these average figures, for comparison with the actual average cost
on the whole work. The cost records show this to be about $2.25 per yd.,
exclusive of power for running the drills, almost exactly what the
following estimates give for theoretical average conditions, although no
effort was made to have this latter compare so closely.

          _Estimated Cost per Drill per Day._

  Drill Runner                            1 at $3.50 per day, $3.50
  Helper                                  1  ”  2.00  ”   ”    2.00
  Nipper                                1/5  ”  1.75  ”   ”    0.35
  Heading foreman                      1/12  ”  5.00  ”   ”    0.42
  Walking boss                         1/50  ”  7.50  ”   ”    0.15
  Blacksmith                           1/12  ”  4.00  ”   ”    0.34
  Blacksmith helper                    1/12  ”  2.00  ”   ”    0.16
  Machinist                            1/12  ”  3.00  ”   ”    0.25
  Machinist helper                     1/24  ”  1.75  ”   ”    0.07
  Pipe fitter and helper               1/50  ”  5.00  ”   ”    0.10
  Oil, waste, blacksmith coal, etc.                            0.24
  Drill steel, 6 in. per shift                                 0.20
                                                              -----
                                                              $7.78

  Average number of feet drilled per cubic yard            3 to 3.5
  Number of feet drilled per drill, per shift            10.5 to 12
  Number of yards per drill, per shift                         3.5±
  Cost of drilling, per yard, $7.78/3.5                      $2.22±

In all the foregoing tables and computations, the quantities used have
been those paid for. The quantity taken out, however, has been 10% more
than that paid for, and 28% more than the contractor was actually
required to take out.

The specifications required that the excavation should be taken entirely
outside of the neat line, as shown on Plate VIII of the paper by Mr.
Jacobs, but not necessarily beyond this line, but that the contractor
would be paid for rock out to the standard section line, which is 1 ft.
larger on the sides and top and 6 in. deeper in the bottom than the neat
line.

A great deal of the extra quantity was due to rock falling from the
core-wall side whenever one working face was behind the other. Blasting
at the face behind generally loosened more or less rock on the core-wall
side of the tunnel which was ahead, in one or two instances breaking
entirely through, as shown in Fig. 2, Plate XXVI, the hole in the
core-wall in this case being utilized by building a storage chamber in
it.

Table 3 gives some of the statistics of drilling in the Simplon Tunnel,
as compared with the drilling on this work, the figures for the Simplon
being taken from papers read before the Institution of Civil Engineers
of Great Britain.

  TABLE 3.
  -------------------------------------------+--------------+----------
                                             |              |
                                             | Bergen Hill. | Simplon.
  -------------------------------------------+--------------+----------
  Drills set up in heading, percentage of    |              |
    total elapsed time                       |      50%     |   60%
  Actually drilling the rock, percentage of  |              |
    total elapsed time                       |      25%     |   50%
  Average advance per round (attack)         |    8.5 ft.   | 3.8 ft.
  Average time for each attack               |   36 hours.  | 5 hours.
  Average advance per day of 24 hours        |     5 ft.    | 18 ft. †
  Depth of holes                             |    10 ft.    | 4.6 ft.
  Diameter of holes                          |    2¾ in.    | 2¾ in.
  Linear feet drilled per hour, per drill    |     2.7      |   7.0
  Linear feet drilled per cubic yard         |     5.0      |   6.0
  Pounds of dynamite per cubic yard          |  3.4 to 5.7  |  8½
  Average depth drilled with one sharpening  |    12 in.    | 6½ in.
  Total number of men per day of 24 hours*   |     450      |  3,300
  -------------------------------------------+--------------+----------

    [* On Bergen Hill Tunnels, for two full working faces at the
    Hackensack end, about 3,000 ft. in from portal (March, 1908). At
    Simplon, two full faces and two headings, at a distance of about
    5,000 ft. in from the portal (January, 1900). These both include
    lining as well as excavation. The lining of the Bergen Hill Tunnels
    progressed about twice as fast as the excavation; it is inferred
    that on the Simplon it progressed at about the same rate as the
    excavation.]

    [† At the Italian end, in Antigoric gneiss, which is stated to be
    very hard rock.]

The figures in Table 3 are for “heading only” in both cases, except for
the last item (number of men), the heading in the Simplon Tunnels being
about 60 sq. ft., as compared with the heading of Method No 4 (which has
been used for comparison), of 210 sq. ft.


_Mucking and Disposal._--The conditions affecting the disposal of the
muck, after blasting, were quite different at the two ends, the grade
descending in the direction of the loads at Weehawken and ascending at
the Hackensack end. At the Weehawken end the mouth of the tunnels was at
the bottom of a shaft some 80 ft. deep, Fig. 2, Plate XXII, the muck in
the tunnel cars being hoisted by elevators to a platform at the top from
which it was dumped into standard-gauge cars supplied by the Erie
Railroad, as shown by Fig. 7; or later hauled to the crusher or storage
pile, some 500 ft. distant, on the north side of Baldwin Avenue. At the
western end, the cars were hauled directly to the surface through the
approach cut, and the material, except that required for concrete and
rock packing, was deposited in the embankment across the Hackensack
Meadows, a haul of from 1,000 to 3,000 ft. beyond the portal.

All disposal tracks were of 3-ft. gauge, the main running tracks being
generally laid with 60-lb. second-hand rails, although some of lighter
weight were used.

Except for about 1,000 ft. in each tunnel at the Weehawken end, where
the muck was loaded by hand, four steam shovels, operated by compressed
air, were used, one at each working face. One of these was a “Marion,
Model No. 20,” weighing 38 tons, the others were “Vulcan Little Giant,”
of about 30 tons each. All these shovels were on standard-gauge track,
and were moved back from 300 to 500 ft. from the working face during
blasting.

  [Illustration: Fig. 7.
  METHOD OF EMPTYING DUMP CARS AT WEEHAWKEN SHAFT:
  FRONT VIEW, SIDE VIEW]

At Weehawken, previous to the time the shovels were installed, the muck
was shoveled by hand into the cars from the bottom of the bench, and the
heading muck was dumped into them from the movable platform (Jumbo)
shown by Fig. 1, Plate XXII. There were three loading tracks at the
face. The cars used at that time were similar to that shown by Fig. 5,
but were about two-thirds the size and had no end door; stop-planks were
supposed to be placed in the ends but seldom were. The loads averaged
about ½ cu. yd. (measured in place). After the shovel was installed the
cars shown by Fig. 5 were used, and the loads averaged nearly 1 cu. yd.

The empty cars were pushed up to the shovel by hand from the storage
track. When loaded, they were given a start with the bucket of the
shovel, and were then allowed to coast by gravity out to the storage
track near the shaft, where they were stopped by placing rolls of cement
bags or burlap on the rails. After the lining was started, the loaded
cars were stopped on the inside of the lining and only sent out over the
single track through this latter at stated intervals, when several cars
followed in close succession, with a long interval which permitted the
concrete to be brought in. The empty cars were hauled back to the
storage track near the working face by mules, one mule usually hauling
two cars at a time.

Up to the time the trap rock was reached, about 1,100 ft. from the
shaft, the excavated material was disposed of by loading it on flat
cars. All the trap, however, was stored to be used later for concrete
and ballast.

When the tunnels were in full working order, sixty muck cars of the type
shown by Fig. 5, were in use, about evenly divided between the two
tunnels. For some time the work was greatly hampered by lack of cars,
and even with the sixty finally obtained, there were many times when
extra cars could have been used to advantage to keep the shovel working.

When mucking by hand, the mucking gangs consisted of from 15 to 20 men.
The maximum output was 50 cu. yd., and averaged about 35 cu. yd. per
shift; there was a great deal of trouble in keeping the gangs full, as
labor at that time was very scarce, and the tunnels were quite wet. The
maximum output of either of the shovels was 159 cu. yd. in one shift,
and the best average in any month--which was between July and December,
1907, during which time only the enlargement and bench of the Central
Shaft headings was being taken out from the western end--was 60 cu. yd.
per shift. As the shovels were generally idle for one shift out of
three, the quantity actually handled averaged 90 cu. yd. per shift
during the shifts the shovel worked. All these quantities were “measured
in place,” and, as previously noted, would be about equal to twice as
much measured loose in the cars.

The shovels at both ends were usually worked with three crews for the
two tunnels; two day crews, one at each shovel, and a night crew which
was used in either tunnel as occasion required. The day crews generally
averaged from 45 to 60 hours overtime during the month, one of them
working during the early part of the evenings in the opposite tunnel to
the night crew. For a short time, when the ventilation at the western
end was very bad, four crews were worked, day and night crews in each
tunnel; but, as a general rule, the method of working three crews was
preferred by the men, and was less expensive for the contractor.

At the Hackensack end, 4-yd., Allison, one-way, dump cars were used,
being handled by “dinky” locomotives, of which there were three in use
up to October, 1907, and four after that. One 15-ton Porter engine, with
10 by 16-in. cylinders, was used outside the tunnels for handling the
trains (from 6 to 8 cars) on the dumps and to the crusher; the other
three, 12-ton Vulcans, 9 by 14-in., were used in the tunnels. About 30
dump cars were in use, and of these there were generally from 3 to 6
under repair.

Generally, 4 cars were hauled out together, although 5 and occasionally
6 were handled. The work was generally arranged so that the heavy
mucking shift alternated in the two tunnels, the two engines being
worked there and a single engine in the other tunnel.

The tunnel engines left the cars on a track just outside the portal,
from which they were made up into trains of from 6 to 8 cars and taken
to the dump or crusher by the large “dinky.”

The muck from the Central Shaft headings was loaded by hand into cars
similar to that shown by Fig. 5, but smaller and having no door at the
forward end. A double elevator took the cars to a platform about 20 ft.
above the surface, where they were dumped by revolving platforms,
similar to those at Weehawken, into storage bins or directly into
wagons. The muck was all hauled away in wagons; part of it was used to
fill some vacant lots, and part was hauled to the crusher at the Western
Portal.

The method under which the best results were obtained was that in which
a full round was blasted every 36 hours, securing an advance of
practically 9 ft. of full section. During the first shift of the three,
as soon as the blasting had been completed and lights strung, the shovel
was moved forward, and cleaned up the floor to the main pile of muck,
the material from the blast being scattered from 150 to 300 ft. back
from the face; during this shift, also, the drillers mucked the heading
and set up their drills, the muckers helping to carry in the columns and
drills. During the second shift the main pile of muck was disposed of,
leaving not more than 2 or 3 hours’ work for the shovel on the third
shift. This left nearly the whole of the third shift for drilling the
lift holes.


_Ventilation._--At Weehawken considerable difficulty was caused by fog
and smoke accumulating in the tunnels after blasting. This was generally
worse on days when the barometric pressure was low outside, and worse in
the North than in the South Tunnel. A 6-ft. fan, driven by an electric
motor, was installed in the cross-passage at Station 274, 900 ft. from
the shaft, the headings at that time being about 300 ft. in advance of
this point, to force the air from the South into the North Tunnel,
drawing it in at the mouth of the South Tunnel and discharging it at the
mouth of the North Tunnel, thus insuring a circulation in both tunnels,
as shown in plan by Fig. 8.

  [Illustration: Fig. 8.]

This necessitated, of course, that the cross-passages between that in
which the fan was placed and the mouths of the tunnels should be blocked
tight. There was some difficulty in keeping this blocking tight, owing
to the force of the blasting blowing out the bulkheads. The fan,
however, did good service when it and the bulkheads were in good order.
The compressed air discharged from the drills kept the headings fairly
clear, as well as that part of the tunnel between the headings and the
fan. The fan was moved ahead to the next cross-passage at Station 277
when the work had progressed far enough, and was used there for some
time; it was found, however, that by the time the excavation had reached
Station 280, about 1,500 ft. from the shaft, there was practically no
further difficulty from fog and smoke. No satisfactory explanation was
found for this, as it would rather be expected that the ventilation and
trouble with smoke and fumes from blasting would be worse as the
distance increased between the mouth of the tunnel and the working face.
One explanation was offered: That the blasting of the softer sandstone
tended to create more and lighter dust than the heavier trap rock;
whether or not this was so, it is a fact that there was far less trouble
with fog and smoke after the sandstone was passed.

At Hackensack, the principal cause of trouble was the smoke from the
“dinky” locomotives. As the tunnels progressed, this gradually became
worse, until a connection was made with the Central Shaft headings.
A fan was installed in the cross-passage at Station 316 (700 ft. in from
the portal), but was never worked properly. Apparently, the men, at
least the walking bosses and foremen, had little faith in the fan as a
means of ventilation; no real attempt was made to keep it in order or
operate it properly, and a great deal of time and money was lost groping
around in the smoke and fog, the density of which increased, not only
with the state of the atmosphere, but also with the direction of the
wind. On some days the tunnels easily cleared themselves, and on others
the smoke was so thick that a candle held at arm’s length could not be
seen. At this end, the South Tunnel was generally worse than the North.
After the headings were holed through between the portal and the Central
Shaft there was very little trouble, there being usually a strong
up-draft through the shaft. This was so pronounced when the wind was
blowing toward the portal, that the moisture-laden air, as it ascended
from the mouth of the shaft, presented the appearance of a heavy
rainstorm with the rain ascending instead of descending. When the wind
was blowing away from the portal, that is, from the southeast, the
effect of the shaft as a chimney was neutralized, and, consequently, the
smoke accumulated in the tunnels. To overcome this, a large blower, with
a fan 9 ft. in diameter, and with blades 4 ft. wide and 2 ft. 3 in.
long, operated by a vertical 12-h.p. engine, was installed at the top of
the shaft, and this kept the tunnels reasonably clear of smoke at all
times. After the bench and enlargement had passed the bottom of the
shaft, the use of the fan was abandoned, as it was found that the
tunnels cleared themselves fairly well, probably owing to the larger
cross-section reaching all the way to the Shaft. What little fog and
smoke there might be did not cause enough trouble to warrant the cost of
running the fan, which, owing to its location, required the whole time
of a mechanic in attendance day and night.


_Lighting._--During the earlier stages of the work, gasoline lamps and
Kitson lights were used. The former, of the familiar banjo type, and a
modification of this, with a section of wrought-iron pipe for the
reservoir, were very unsatisfactory, and were out of repair and leaking
a large proportion of the time. The Kitson lights were given only a
short trial, but were found unsatisfactory, owing to the necessity of
moving them frequently and having to set them up in insecure positions.
Electric lights were installed by Mr. Bradley, on his assumption of the
contract.

The number of lamps maintained in each of the tunnels for the excavation
was approximately as follows:

  At the main working face                 From  8 to 10
  On and around the shovel                   ”   9 to 12
  Between the portal and the working face    ”  60 to 80

The cost of lighting for the whole work averaged about 15 cents per
cu. yd., which is quite large. This was mainly due to the fact that
current was bought from outside sources during a large part of the time
(one-third of the yardage). Part of this current cost 5 cents per
kw-hr., and there were fairly heavy charges for connecting the tunnel
wiring system with the source of supply. Current bought from the Public
Service Corporation cost from 10 to 12 cents per kw-hr. delivered at the
mouth of the tunnel.


_Pumping._--The quantity of water encountered during the excavation of
the tunnels, measured somewhat roughly, was approximately as follows:

  At Weehawken        74 gal. per min.
  At Central Shaft     1  ”    ”   ”
  At Hackensack       18  ”    ”   ”

The water at the Weehawken end had to be pumped from the bottom of the
shaft, a lift of about 90 ft., while at the Hackensack end it had to be
pumped back from the face up grade to the portal.

The cost of pumping was about $100 to $125 per month for labor for the
whole work, besides the cost of the plant (about $1,200) and the power
for running it.


PROGRESS.

The total time elapsed from the time of starting work at the Weehawken
end, in May, 1905, to the completion of the excavation, in May, 1908,
was almost exactly three years. Of this time about 40 days were lost in
February and March, 1906, when work was stopped by the Receiver of the
Shields Company, the total number of days actually worked being about
940, giving an average progress of 6.26 ft. per working day in each of
the two tunnels, which, omitting the Central Shaft headings, gives an
average rate of progress for each working face, of 3.13 ft. per day.

These 940 days include practically all the time elapsed, except Sundays
and such few holidays as were observed. For some of this time, work was
being carried on at only one or two points; the time, therefore,
represents practically the total possible working time during the period
covered.


_Progress at Weehawken._--At Weehawken the total number of days worked
was 763, divided as follows:

186 days in timbered section, about 426 ft., an average rate of 2.3 ft.
    per day in each tunnel;

176 days in hard sandstone, about 563 ft., an average rate of 3.2 ft.
    per day in each tunnel;

112 days in hard trap, about 267 ft., an average rate of 2.4 ft. per
    day in each tunnel;

289 days in ordinary trap, about 1,316 ft., an average rate of 4.55 ft.
    per day in each tunnel.


_Progress at Central Shaft._--At Central Shaft the average length driven
per day in each of the four headings is shown by Table 4.

TABLE 4.

  -----------+----------------+-----------------+---------------------+
   Location. | Number of days | Total length of |  Average length of  |
             |     worked.    |   heading, in   |  heading driven per |
             |                |     feet.       | day worked, in feet.|
  -----------+----------------+-----------------+---------------------+
             |                |                 |                     |
     N.E.    |      227       |      446        |         1.96        |
     S.E.    |      168       |      346        |         2.06        |
     N.W.    |      272       |      768        |         2.82        |
     S.W.    |      234       |      698        |         2.98        |
  -----------+----------------+-----------------+---------------------+


_Progress at Hackensack._--At Hackensack the total number of days worked
on the tunnels proper, all in trap rock (omitting the cut and cover) was
about 792, divided as shown in Table 5.

  TABLE 5.

  ------------------------------+----------+----------+----------+
                                |Number of |          | Average  |
                Location.       |  days    | Advance. | advance  |
                                | worked.  |          | per day. |
  ------------------------------+----------+----------+----------+
  Station 323 to Central Shaft  |          |          |          |
    headings                    |   492    |   1,450  |   4.5    |
  Bench and enlargement of      |   159    | { 1,150* |   7.2*   |
    Central Shaft headings      |          | {   906† |   5.7†   |
  Central Shaft headings to     |          |          |          |
    Weehawken headings          |   141    |     620  |   4.4    |
  ------------------------------+----------+----------+----------+

    [* Actual advance.]

    [† Equivalent linear feet of full section tunnel.]

The best month’s work in each location was as follows, the actual
yardage excavated and paid for being reduced to equivalent linear feet
of full section. The tunnels were generally taken out to full section,
except for a small amount left in the bottom, which latter reduced the
equivalent linear feet of full section to about 95% of the actual
advance at the face.

  _Weehawken._--
                                                            Feet
                                                    Linear  per
                                                     feet.  day.
  Full timbered section, North Tunnel   Nov., 1905,    87 = 3.0
  Sandstone                ”     ”      May,  1906,   109 = 3.9
  Trap (normal)          South   ”      July, 1907,   144 = 5.3


  _Hackensack (All trap)._--
                                                          Feet
                                                  Linear  per
                                                   feet.  day.

  Portal to Central Shaft headings,
    South Tunnel                        May,  1907, 139 = 5.0
  * Enlargement of headings,
       ”     ”                          Nov., 1907, 175 = 6.0
  Central Shaft headings to Weehawken
    headings, North Tunnel              Apr., 1908, 145 = 5.2

    [* The actual advance of the bench this month was 202 lin. ft.]


_Central Shaft Headings._--During April, 1907, 122 lin. ft. of heading,
averaging 3.8 cu. yd. per lin. ft., were taken out in the South Tunnel,
west of the shaft. This was equal to 5.0 ft. per day for the 24 days
worked.


_The Best Week’s Work._--The best week’s work at either of the main
working faces, when the full section was being excavated in trap rock,
was 803 cu. yd., equal to 41.8 lin. ft. of full-section tunnel, or an
average of 6.0 lin. ft. of full section per day; this was from the South
Tunnel at Hackensack for the week ending January 11th, 1908.


_The Best Yardage._--The largest number of yards taken out in any one
week from one working face was 1,087, equivalent to 56.6 lin. ft. of
full section, or an average of 8.1 lin. ft. of full section per day.
This was bench and enlargement only (Central Shaft headings) in the
North Tunnel, Hackensack, for the week ending October 19th, 1907.

The largest yardage for the whole work in any one week was 3,238 cu. yd.
from four working faces--two at Weehawken in full section and two at the
Hackensack bench and enlargement (Central Shaft headings). This was
equivalent to 168.4 lin. ft. of full-section tunnel, or an average of
6 ft. per day from each working face.


_The Best Month’s Work._--The best month’s work with each of the four
methods of drilling the headings, as shown in Figs. 1, 2, 3, and 4,
where the work was straight forward and the full section was being taken
out, was as follows:

  Method No. 1      About  90 ft. in sandstone.
    ”    No. 2        ”   100  ”  in trap.
    ”    No. 3        ”   137  ”  in trap.
    ”    No. 4        ”   145  ”  in trap.

In regard to these figures it should be noted, as stated previously,
that the organization of the men and plant was not properly completed
until near the time Method No. 4 was put in operation.

In Fig. 9 is shown graphically the relation of the progress to the time
elapsed in the North Tunnel, the diagram for the South Tunnel being
almost exactly the same.


PLANT.

The plant installed by the John Shields Construction Company, and taken
over by Mr. Bradley, was composed very largely of second-hand material,
and eventually most of it had to be replaced. Insufficient and
inefficient plant and delay in installation were largely responsible for
the small progress made by the Shields Company, and Mr. Bradley’s
endeavor to utilize this plant not only caused much delay during the
first 8 or 10 months after he started work, but also involved large
expense.


_Power Plant._--At Weehawken the plant installed by the Shields Company
consisted of three old locomotive boilers, each having a nominal
capacity of about 125 h.p., and one Rand and one Ingersoll-Sergeant
compressor, each of a rated capacity of about 1,250 cu. ft. of free air
per min. compressed to 100 lb.

To this Mr. Bradley added two more second-hand locomotive boilers, and
another Rand compressor of the same type and capacity as the first. The
theoretical steam capacity of each of the five old locomotive boilers
was about 4,250 lb. per hour, or a total capacity of 21,250 lb. per
hour.

  [Illustration: Fig. 9.
  PROGRESS PROFILE--NORTH TUNNEL]

Theoretically, the demand on this steam was:

                                                     Pounds per hour.

  Three compressors, about 5,600 lb. per hour each            16,800
  One dynamo                                            About  1,000
  One 500-gal. pump                                       ”    1,000
  One hoisting engine for elevators                       ”    2,000
                                                              ______
        Total                                                 20,800

Actually, there was considerable deficiency of steam when an endeavor
was made to work the three compressors at their full capacity.
A separate boiler was afterward installed to run the hoisting engine
for the elevators and the pumps, thus leaving a requirement of only
approximately 18,000 lb. of steam per hour, but even this was beyond the
capacity of the boilers, especially as one was almost always out of
commission.

The two Rand compressors were 24 by 24 by 30-in., straight-line,
one-stage, steam-driven, with a nominal capacity of 1,250 cu. ft. of
free air per min. at 80 rev. per min. The Ingersoll-Sergeant was of
similar type and capacity. Therefore, the theoretical quantity available
was 3,750 cu. ft. of free air per min.

The theoretical air requirements (as taken from manufacturers’
catalogues) were:

                                            Cubic feet of free
                                              air per minute.

  20 Rand slugger drills (12 by 174)             2,088
   2 Little Giant shovels
       (taking air two-thirds of the time)       1,100
                                                 -----
  Total                                          3,188

This estimate, based on the assumption (given in the catalogues) that
the drills would be working about three-fifths of the time, and the
shovels about two-thirds of the time, left apparently an ample margin
between the full capacity of the compressors and the requirements for
the drills; as a matter of fact, however, it was seldom that more than
80 lb. of air was available, and the pressure often dropped to 60 or 50
lb. at the compressors. During the time this plant was in use the
greatest distance to the drills was about 1,500 ft.

As this plant proved to be entirely inadequate to the demands, an
arrangement was made with the O’Rourke Construction Company on August
17th, 1906, whereby they agreed to supplement the air supply by 1,000
cu. ft. of free air per min. at 100 lb. pressure. This arrangement was
not altogether satisfactory, and finally (on December 5th, 1906) an
arrangement was made with the same company to supply air up to 4,000 cu.
ft. of free air per min. at 100 lb., and the old plant was shut down.

The new plant had been in use previously in the construction of the
River Tunnels. The air from it was compressed to 40 lb. by low-pressure
machines, one being used all the time and two when necessary. These
machines were built by the Ingersoll-Sergeant Company, the engines being
of the Corliss duplex type, cross-compound steam, with simple duplex air
cylinders, each compressor having a capacity of nearly 4,000 cu. ft.
of free air per min. This air, at 40 lb., was delivered to an
Ingersoll-Sergeant high-pressure machine, having Corliss cross-compound
engines, 14 by 26 by 36-in., with air cylinders of the piston inlet
type, 13¼ by 36-in., which compressed it to 100 lb. The capacity of this
latter machine, taking air at normal pressure, is 920 cu. ft. of free
air per min. working at 85 rev. per min.; by taking the air at 40 lb.,
and working at a somewhat higher speed, this machine alone supplied all
the air used at the Weehawken end (approximately 4,000 ft.) from
December, 1906, to November, 1907, and, with very few exceptions, the
pressure was steadily maintained at from 90 to 100 lb., there being no
break-down of any kind.

At Hackensack the plant taken over by Mr. Bradley consisted of six old
locomotive boilers and four Rand compressors, all of the same type as
those at Weehawken. To this he added two second-hand marine boilers,
each of a stated capacity of about 350 h.p., and two more Rand
compressors of the same type and capacity as the others, making the
total theoretical steam power available approximately 1,450 h.p., with a
compressor capacity of approximately 7,500 cu. ft. of free air per min.,
equal to about 1,500 h.p., allowing for 15% of loss.

Nowhere near the theoretical steam power was ever developed from the
boilers. The tubes of the old locomotive boilers were filled with mud in
many cases, and were always leaking. The marine boilers were not
properly installed to give the best results, and it was seldom possible
to work more than four compressors at once, or to keep the air pressure
at the power-house much greater than from 70 to 80 lb. at any time.

This plant had been built by the Shields Company on the meadows
alongside the Erie and New York, Susquehanna and Western Railroads, and
the foundations were not made sufficiently strong to resist the effect
of the vibration caused by the passing trains. It was impossible to keep
the steam connections tight, and there was not only the loss of steam
due to leaky joints, but positive danger of one of the main steam lines
breaking entirely. After attempting to operate this plant for nearly 5
months, Mr. Bradley determined to abandon the site and the boilers, and
build a new plant, farther back from the railroad, on solid ground, in
such a position that a spur track could be built to a coal trestle in
front of the boilers.

Two pairs of Stirling boilers, with a total capacity of 2,000 h.p., were
installed. As a rule, at times of maximum demand, three of the boilers
were in use; after the Central Shaft was stopped, two were generally
sufficient, until, toward the latter part of the excavation, the losses
in the transmission of the air made it necessary to keep three going.

Eight compressors (the six old ones with two brought from Weehawken),
were installed in the new power-house. All were of the same type,
namely, Rand, straight-line, steam-driven, 24 by 24 by 30-in., each with
a nominal capacity of 1,250 cu. ft. of free air per min. Seven of these
were generally worked to their full capacity in order to keep up the
necessary supply of air.

The maximum requirements of air at this end were primarily estimated as
follows:

  Central Shaft, four headings              24 drills.
  Hackensack, two working faces             20 drills.
                                            ----------
        Total                               44 drills.

                                            Cubic feet of free
                                            air per minute.

  44 Slugger drills (25 by 174) require       4,350
   2 Steam shovels                            1,600
     Pumps and machine-shop, say              1,000
   4 Hoisting engines, placing concrete       2,000
   4 Derricks                                 2,000
                                             ------
           Total                             10,950

The theoretical capacity of the whole eight compressors was:

  1250 × 8 = 10,000 cu. ft. of free air per min.

It was considered that not more than two-thirds of the above equipment
would be working at the same time; the actual requirement, therefore,
was taken at about 8,000 cu. ft. of free air per min., thus leaving a
margin of one spare compressor.

As actually worked out, there were probably never more than eight drills
working at any one time at the Central Shaft, and this work was entirely
suspended in June, 1907, before there was any demand for power in
connection with the tunnel lining. The heaviest actual requirement,
therefore, was approximately as follows:

  (_A_) _Previous to June 25th, 1907:_

                                   Cubic feet of free
                                   air per minute.

  40 Drills (22 by 174)              3,828
   2 Shovels                         1,600
     Pumps and machine-shop, say     1,000
   2 Derricks                        1,000
                                     -----
          Total                      7,428

  (_B_) _After November, 1907_ (_after completion of enlargement of
  Central Shaft headings_):
                                     Cubic feet of free
                                     air per minute.

  32 Drills (17 by 174)                2,958
   2 Shovels                           1,600
     Pumps, etc                        1,000
   3 Hoisting engines on concrete,
       each working one-third time       500
   2 Derricks                          1,000
                                       -----
          Total                        7,058

The average number of drillers per shift was about 25 at the two main
working faces. There were also from 5 to 10 drills trimming and cleaning
up for concrete, say an average of 7, making 32 in all.

After November 1st, it actually required three boilers under steam all
the time, and not less than seven compressors running at full capacity,
to keep the air at proper pressure, the theoretical capacity of the
compressors being 8,750 cu. ft. of free air per min., as against 7,000
to 7,400 cu. ft., the theoretical maximum requirement.

Some of this deficiency was due to losses in transmission, part also was
due to the fact that the actual was probably considerably below the
theoretical capacity of the compressors.


ACCIDENTS.

Two accidents occurred to the powder magazines, the causes of which were
never absolutely determined. The first occurred on January 10th, 1907,
when the dynamite burned up without exploding. The second accident was
on March 3d, 1907, when an explosion occurred which damaged property
over a very large area, but did not involve any serious injury to
persons, only one man being slightly hurt.

The only serious blasting accident in the tunnels occurred on January
26th, 1908, and was due to a premature blast, the cause for which could
not be ascertained.


_Contractor’s Organization._--The work was in general charge of a
superintendent, and, during the time it was being carried on at both
ends, an assistant superintendent had charge at night. At each end there
was a day and a night walking boss, who had general supervision of the
men in the tunnels, the day walking boss being the superior, and
responsible for the general conduct of the work at his end, both day and
night. Two 10-hour shifts were worked, thirteen shifts every two weeks,
no work being done on alternate Sundays and Sunday nights. With the
exception of the walking bosses and the master mechanic, all the men
changed from the day to the night shift every two weeks.

The organization was approximately as follows, for each shift:

  _General_--_Both Tunnels._

  1 Master mechanic (days only),
  1 Machinist,
  1 Engine runner,
  2 Firemen,
  2 Oilers,
  1 Electrician and helper,
  1 Drill machinist and helper,
  3 Blacksmiths and helpers,
  1 Powderman,
  1 Walking boss,
  4 Locomotive engine runners,
  4 Brakemen,
  1 Switchman,
  1 Foreman on dump,
  6 Men on dump,
  1 Foreman on track,
  6 Men on track.

  _In Each Tunnel._

  _Drilling and Blasting._
   1 Foreman,
  12 Drillers,
  12 Helpers,
   1 Nipper,
   1 Pipe-fitter.
  _Mucking._
   1 Shovel engineer,
   1 Cranesman,
   1 Muck boss,
  12 Muckers.


RECORDS.

The records of the work have been based largely on the reports of the
day and night inspectors, which were made out on regular forms.

A daily report card was made out each morning and forwarded to the
office of the chief engineer. It covered the work done for the previous
24 hours, up to 6 o’clock each morning.

A telephone report was made to the resident engineer by the inspectors
each day at 8.30 A.M., giving the conditions, number of men, etc., at
the opening of the day’s work.

A daily progress profile, on 10 by 10 to the inch cross-section paper,
covering the whole length of the tunnels, was kept in the office of the
resident engineer. This was mounted in sections, on a piece of
composition board, and hung on the wall for convenient reference. The
information, showing the progress up to 6 o’clock each morning, was
shown on the report of the night inspector, and was plotted on this
profile at 7 o’clock each morning. The plotting was left in pencil, and
each month’s work was colored in. A progress profile was taken by the
men of the alignment corps each Saturday morning and plotted by them,
alternate weeks being in red and blue ink on the same profile.

A chart showing the number of drills working, time worked, blasting
periods, etc. (Plate XXIII), was plotted each morning and was extremely
useful, not only in keeping in touch with the work, but in compiling
many of the statistics used in the preparation of this paper. These
cross-section sheets were ruled 12 by 12 to the inch, thus giving one
space per hour horizontally. In the top vertical space are shown the
heading drills, their time of stopping and starting, and their number,
each heavy line representing one drill. In the next space below are
shown the drills on the bench, lift holes, etc.

The blasting time is shown by the portion hatched (shown in red on the
original), which covers the whole vertical space when a complete round
of both heading and bench is blasted, and only part, top or bottom, as
the case might be, if only one or the other. The number of drillers and
muckers at the main working face is shown, and below that (in red ink on
the original) the number of cubic yards handled each shift. The time the
shovel is working is shown by the heavy line filling a whole space; and
the air pressure, platted from the recording gauge charts, is shown in
the space below.

A combination daily and weekly report, showing the total number of men
working on each section, and the number of cubic yards excavated, was
entered every day and kept on a filing board in the office of the
resident engineer, and a copy was sent to the main office at the end of
the week, with such notes on the back as might be necessary, or of
interest.

A report was made out weekly and sent to the contractor’s
superintendent, showing any deviations from grade, any tight places, and
the station of bench and headings.

A monthly report was made to the chief engineer, giving detailed
statistics of the amount of work done, etc., plant installed, and short
notes of any matter of interest affecting the work in any way.


TUNNEL LINING.

_Preliminary Considerations._--For the placing of the concrete lining, a
sub-contract was given to Messrs. King, Rice and Ganey, by Mr. Bradley,
which provided substantially that all materials should be supplied by
him, and delivered to the sub-contractors at track level, at or near the
point in the tunnel at which they were to be placed, and that he would
supply light and power; the sub-contractors were to supply the plant,
forms, and labor necessary for placing the concrete and water-proofing,
building the conduit lines, manholes, etc., etc., to complete the
lining, the general form of which is shown on Plate VIII of the paper by
Mr. Jacobs, and in Fig. 10. The latter also shows the different sections
into which the lining was divided for purposes of construction, and the
nomenclature adopted for each. It may be noted, incidentally, that the
cubic contents of the lining per linear foot of tunnel is almost exactly
half the quantity excavated, out to the standard section lines, and as
there was some excavation outside of these lines, all of which had to be
replaced, the actual quantity of material which had to be brought back
into the tunnel was quite a little more than half the quantity taken
out. It will be evident, therefore, that the question of transportation
was an important one.

  [Illustration: Fig. 10.
  SKETCH SHOWING DIVISION OF LINING FOR PURPOSES OF CONSTRUCTION,
  AND NAMES OF SECTIONS]

An essential part of the agreement with the sub-contractors provided
that the operations incident to the placing of the lining should be
carried on so as to provide at all times space for a single track of
3-ft. gauge, running through the work, and the necessary clearance for
the locomotives and cars used in hauling out the muck. A clearance
diagram of one of the “dinkys” used in the tunnels, and its relation to
the forms used, is shown by Fig. 12 and also by Fig. 16, the 4-yd.
Allison cars, used for handling the muck, taking practically the same
width, although they were not quite as high. This requirement and the
limited space available must be kept in mind in considering the design
finally adopted for the forms and plant required in placing the lining.
It should also be kept in mind that, with the rolling stock used, there
was only room for a single track through that part of the tunnel where
any concrete had been built. As the concrete progressed, therefore, the
length of single track was necessarily lengthened, and the problem of
transportation was made increasingly difficult.

In working out a design for the bench-wall forms, another highly
important and controlling factor, which had to be considered, was the
arrangement of the conduit lines, as shown in the general
cross-section.[2]

    [Footnote 2: Plate VIII of the paper by Mr. Jacobs.]

The quantities of the various materials in the lining, per linear foot
of tunnel, were as follows:

  Concrete                                         7.64 cu. yd.
  Rock packing: Paid for           1.48 cu. yd.
  Outside standard section line    1.74  ”   ”
                                   ------------    3.22  ”   ”
  Iron and steel                                  44.2  lb.
  Vitrified conduits                              84.0  duct ft.
  Water-proofing                                  13.0  sq. ft.
  Flags                                            3.3   ”   ”


_General Methods._--The lining was started at both ends of the tunnels
before the headings were finally holed through, so that there was
practically a separate organization at each end, each in charge of one
of the members of the firm. The work at the Weehawken end was started
first, and the plant and scheme of working adopted there was thoroughly
tried out before the plant for the western end was built, consequently,
the latter was somewhat more efficient, being designed in the light of
the experience gained at the Weehawken end.

The general sequence of the plan first adopted in placing the concrete
is shown by Fig. 10. The concrete was first placed in the foundations up
to the elevation of the bottom of the conduit bines, this work, of
course, being kept well in advance; next followed, in the order named,
the sand-walls, water-proofing, conduits, bench-walls, and finally the
arch. The foundation was built in any convenient lengths, multiples of
16 ft., the length of one section of form, the sand-walls in lengths of
from 25 to 35 ft., the bench-walls in 25-ft. lengths, and the arch in
10-ft. lengths. Concrete was placed during the day shift only, the forms
being moved partly at night, and partly on the alternate days when
concrete was not being placed in them.

Five gangs were organized at each end, the first placed concrete in the
foundations in both tunnels, as the excavation was ready. In each tunnel
there was a gang which built sand-wall one day and bench-wall the next,
the two tunnels alternating so that only one bench-wall was built each
day, and finally a gang in each tunnel building arches, a 10-ft. section
being completed each day. During the night shift, the arch forms and
travelers were moved, and all other forms, etc., were made ready for the
concrete to be placed the following day. Some of the conduit laying was
done by the night shift, but part of it was necessarily done during the
day, as the concrete was built up. A small gang was kept busy in both
tunnels, during the day shift, laying conduits and water-proofing. The
latter two operations were generally performed by the same gang.

This organization, of course, required considerable regularity in the
work, and this was finally attained, but at the beginning many sections
were often not finished on time, thus creating considerable confusion.
The progress possible with this organization (finally maintained with
great regularity) was 75 ft. of bench-wall and 60 ft. of arch per week
at each of the two working faces in each tunnel. This allowed the
bench-wall to gain considerably on the arch, and therefore at a suitable
point, as shown on the progress diagram, Fig. 9, a third pair of arches
was started, one in each tunnel, increasing the progress on the arches
to 180 ft. per week in each tunnel.


_Mixing and Transportation._--All the concrete used on this section was
mixed in Hains mixers, one being at each end. At the Weehawken shaft the
mixer was installed in the framework supporting the head-house and
elevators; and storage bins were arranged above, as shown by Fig. 11,
_A_, the whole structure being somewhat strengthened to allow this to be
done. At the western end the mixer was placed immediately under the bins
of the stone crusher, as shown by Fig. 11, _B_, the track below being
connected directly with the tunnels. The stone bin under the screen of
the crusher plant at the Hackensack end was divided into three parts,
the center being filled with sand by a derrick having a clam-shell
bucket, the other two with stone directly from the screen above.

This type of mixer proved very efficient on this work. The largest
number of full batches (0.8 cu. yd.) mixed in one plant per hour was
about 35; the largest number per day of 10 hours was about 240; but the
apparatus was never worked to its full capacity, the quantity of
concrete which it was possible to use being limited by other
considerations.

  [Illustration: Fig. 11.
  _A_ CROSS-SECTION OF HAINS MIXER INSTALLATION, AT WEEHAWKEN SHAFT
  _B_ CROSS-SECTION OF HAINS MIXER INSTALLATION,
    STONE AND SAND BINS ABOVE AND SCREEN OF CRUSHER, AT HACKENSACK
    PORTAL]

The concrete for the foundations was hauled in steel, =V=-shaped,
dumping cars holding about 1 cu. yd., and the concrete for the
bench-walls and arches in Stuebner, 1-yd., bottom-dumping buckets placed
on small flat cars, as shown by Fig. 1, Plate XXIV. Rock packing was
handled in Allison 4-yd. cars and also in the cars shown by Fig. 5,
as well as in the Stuebner buckets, the latter, however, being most
generally used. Mules were used for a short time at the Weehawken end to
haul the concrete in, but proved entirely inadequate to haul the loaded
cars up the 1.3% grade, and locomotives were substituted after the
headings were holed through. At the western end the cars were allowed to
coast in, and, up to the time the headings were holed through, were
hauled back by mules; after that they were pushed out by a locomotive
which had gone in ahead of them. As a rule, from 8 to 10 cars of
concrete and rock packing were sent in, one after the other, in proper
order, a boy riding on each car and stopping it at the proper place; all
these cars were pushed out together when empty.

  [Illustration: Plate XXIV.
  Fig. 1: K 131. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels) Weehawken Shaft, North Tunnel. Rear view of conveyor for
  concrete, showing method of hoisting bucket from car on track in
  hopper over belt. June 7, 07.
  Fig. 2: K 130. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels) Weehawken Shaft, South Tunnel. View showing waterproofing
  (extreme left) portion of completed sand wall, sand wall forms,
  traveller and end of conveyor overhead. July 22, 07.
  Fig. 3: K 148. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels) Weehawken. View showing method of placing concrete in
  forms. Hoisting apparatus and bucket in background. Sept. 24, 07.
  Fig. 4: K 154. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels) Weehawken Shaft, North Tunnel. Method of placing concrete
  in bench walls. Top of waterproofing suspended from top of sandwall.
  Oct. 21, 07.]

During the time the excavation was being carried on simultaneously with
the lining at the Weehawken end, the rock packing was loaded at the
working face and sent out to the point where it was to be used; after
that the rock packing was sent in from outside from the reserve pile on
the north side of Baldwin Avenue.

At the western end the larger part of the rock packing was sent in from
outside, but occasionally, during the time the excavation was going on,
the cars from the heading were stopped at convenient points, generally
under the gantries, where the lining was being placed, and whatever
stone could be utilized was sorted from the top and passed up to the
platforms above.

After the headings were holed through, there was considerable difficulty
at times in getting a sufficient supply of concrete and rock packing
into the tunnel at the time it was required, and while undoubtedly the
transportation facilities may have had some influence in this, the
principal trouble lay in the difficulty of securing a sufficient supply
of proper stone for rock packing, and for the crusher.

While the excavation was progressing, the cars of muck, as they came
from the headings, were taken directly to the crusher and dumped into
it, the proportion of fine material being fairly constant and the supply
regular. At this time, also, a portion of the rock not required at the
crusher was dumped along the edge of the bank on the south side of the
approach, the larger stones rolling to the bottom where they were easily
available to be loaded into cars for rock packing, being entirely free
from the fine material; as this stone at the bottom of the bank was used
up, the supply was renewed, the rock suitable for rock packing being
automatically separated from the fine material as it rolled to the foot
of the slope.

After the excavation was completed, however, it was necessary to go into
the bulk of the storage piles to get material for the crusher and for
rock packing, and then the difficulties were materially increased by the
large quantity of fine material encountered, the proportion remaining
after the rock packing had been sorted out being too large to send
through the crusher. It was not only the handling over of this fine
material which caused delay, but the difficulty of disposing of it. On
rainy days the trouble was increased by the difficulty of getting men to
work in the open.

The delays due to transportation were usually caused by derailments,
which were more numerous than they should have been, and were due to the
condition of the rolling stock rather than to that of the track. These
delays, especially when they occurred in the early part of the day,
greatly increased the cost, by necessitating over-time work; a delay of
1 hour in the forenoon generally meant 2 hours’ work after 6 o’clock to
finish the day’s work.

The average number of cars handled (round trips of 1 car) during a day
(two 10-hour shifts) at the Hackensack end during January, 1908, when
the excavation and lining were in full swing, was about 125 cars of muck
and 200 cars of lining material, the former being hauled by locomotives
and the latter by mules.


_Methods of Handling Concrete in the Tunnels._--The concrete for the
floor, ditches, and foundations, was brought into the tunnel in
=V=-shaped steel, dumping cars, and dumped as near as possible to the
place it was to occupy.

The concrete for the arches and bench-walls was loaded at the mixers
into 1-yd., Stuebner, bottom-dumping buckets which just held a 4-bag
batch. These buckets were placed on small flat cars, hauled into the
tunnel, placed beneath the traveling gantry, as shown by Fig. 1, Plate
XXIV, and hoisted to the platform above.

These traveling gantries, the details of which are shown by Fig. 12,
consisted essentially of platforms at each end of which an =A=-frame was
erected; the latter supported at their apexes two =I=-beams, from the
lower flanges of which was suspended a traveling block, shown at _A_,
Fig. 12, and through which the hoisting rope was rigged. The buckets
were hoisted through an opening in the platform and then moved along to
where they could be dumped. The platforms were supported on wheels
traveling on rails laid on the concrete of the foundation (for the
bench-wall gantries) or on top of the bench-wall (for the arch
gantries).

Each of the first two of these traveling gantries used was equipped with
a belt conveyor working on a cantilever arm, as shown by Figs. 3 and 4,
Plate XXI, and Figs. 1 and 2, Plate XXIV. In using these belt conveyors,
the concrete was dumped from the Stuebner bucket into a hopper, Fig. 1,
Plate XXIV, with an adjustable slot in the bottom, under which the belt
ran.

  [Illustration: Fig. 12. [Full Page]
  DETAILS OF TRAVELING GANTRY USED IN THE CONSTRUCTION OF THE TUNNEL
  LINING:
    SECTIONAL ELEVATION
    CROSS-SECTION
    A. DETAIL OF TRAVELING BLOCK
    B. DETAIL OF TOP SHEAVE
    C. DETAIL OF LOWER SHEAVE.]

It was the original intention, in designing the conveyor, that the end
of the cantilever arm should be swung from one side of the tunnel to the
other, and that the traveler should be moved backward or forward, as
might be required, and thus deliver the concrete from the end of the
belt directly over the place in which it was to be deposited in the
bench-walls. As a matter of fact, it was found impractical in operation
to move the gantry readily, owing to its great weight, which was
supported on only four ordinary car wheels and their bearings, and it
was found more convenient to leave the arm in one position near the
center, letting the concrete drop on the platform above the bench- or
sand-wall forms, whence it could be shoveled into place, than to attempt
to move it as had been intended. Both of these difficulties might
possibly have been overcome by modifications in the design of the gantry
and conveyor, had this method of handling the concrete seemed otherwise
desirable.

The principal difficulty with its use, however, was the inability to
take care of more than one batch of concrete at a time. When one batch
had been dumped into the hopper, a second could not be disposed of until
the first had nearly all run through on the belt, and this took from 7
to 20 min., varying with the consistency of the concrete, etc. In a few
instances, where there happened to be some fairly dry batches, the
concrete could not be started through the slot at all, and had to be
shoveled out of the hopper. On the other hand, it is stated that some
batches, under favorable conditions, passed through in about 2 min., but
this was quite exceptional, and the operation was irregular and
uncertain.

Before the final method of handling the concrete was adopted, a trial
was made of two forms of cars and buckets, to be used on the top
platform, as shown by Figs. 3 and 4, and Plate XXIV. In the method shown
by Fig. 3, Plate XXIV, the concrete was hoisted in the regular Stuebner
buckets, one of which can be seen suspended in the background of this
photograph, and dumped into the car shown, which was mounted so that it
could be revolved in a horizontal plane. It was intended to move this
car on the tracks to the point at which the concrete was required, and
dump it directly through a chute into the bench-walls. This car was
abandoned, as there was a great deal of difficulty in turning it when it
was loaded, and in several instances it had to be dumped straight ahead
in the middle of the platform and the concrete shoveled into the forms.
This method was also objectionable when the bucket was dumped, inasmuch
as the force of the impact of a whole batch of concrete dumped from such
a height into the forms, not only tended to throw the conduits out of
line, and to break them, but also caused considerable strain on the
forms.

The bucket shown by Fig. 4, Plate XXIV, was next tried. It had a
slanting bottom and a door opening at the side. It was filled at the
mixer, came into the tunnel on a small flat car, and was hoisted and
placed on a similar car on top, as shown. This bucket was not
successful, as its great weight made it difficult to handle, and it
generally required a man to shovel the concrete out, which latter, of
course, had been pretty well compacted in the bottom of the bucket by
its trip from the mixer. All these cars were hauled backward and forward
on the top platform by a rope running to the winch on the hoisting
engine on the traveling gantry.

Aside from the fact that neither type was a success, neither of these
schemes was much improvement over the belt, inasmuch as only one batch
could be handled at a time, owing to the necessity of using the engine
to haul the cars back and forth on the platform. The final solution was
found in the use of the traveling gantry, shown by Fig. 12 and Fig. 1,
Plate XXVI, the latter being one of the arch gantries. The gantry used
for the bench- and sand-walls was supported on framed bents on wheels
running on rails laid on the foundation; that for the arch was the same,
except that the high-framed bent was dispensed with, the side-sills
resting directly on the journals of wheels traveling on rails on top of
the finished bench-wall.

These gantries were used only as a means of hoisting the buckets and
moving them along to where they could be dumped directly on the
platform, whence the concrete was shoveled into wheel-barrows, which
could be dumped directly into the bench-walls; or, in the case of the
arches, shoveled from the platform of the gantry to the intermediate
platform on the arch ribs, and thence directly into the arch. This use
of wheel-barrows, though apparently a somewhat crude method and a
retrogression from the use of the belt conveyor, proved very successful,
and really involved no more labor than did the conveyors, although this
might not have been the case had these latter worked as they were
originally designed to.

The method finally adopted allowed as many as four buckets to be dumped
on the platform on one end of the arch gantry at one time, and eight on
one end of that used for the bench-walls, the workmen handling about
three of these latter into the forms by the time the last of the eight
was dumped. It required about 1½ min. to place a car under the gantry,
hoist the bucket, dump, close it, and return it to the car below.

Rock packing was stored at the other end of the platform, for use as
required, when it was not handled directly from the end nearest the
work. This method allowed the concrete and other materials to be brought
in in trains at infrequent intervals, and provided a sufficient supply
of material on hand so that the men handling it on top could be kept
steadily at work.

Each hoisting engine on these gantries had 7 by 10-in. cylinders, and a
double drum; some of them were Lamberts and some Mundys, operated by
compressed air.


_Ditches, Floor and Foundations._--The first method of building the
foundation was that shown by Fig. 13, _A_; no attempt was then made to
build the ditch, or floor, the intention being to leave these until the
completion of the remainder of the lining. In building the bench-wall on
this foundation, however, it was found difficult to secure the bottom of
the forms properly (Fig. 2, Plate XXV), so as to prevent any give, as
the material under the track was not solid enough to brace against. It
was decided, therefore, to build the whole of the ditch (see Fig. 13,
_B_) so that the bottom of the forms could be braced against the solid
concrete. At the beginning of the work, the face of the bench-wall was
built up to the level of the bottom of the conduits with the foundation;
if, therefore, in placing the concrete above this level, extreme care
were not taken to get a tight fit between the bench-wall form and the
lower face, and then to hold it rigidly in place, the result was a
rather unsightly horizontal joint high enough to be plainly visible. The
position of this joint may be seen in Fig. 2, Plate XXV, which shows the
first section of bench-wall built. Several subsequent sections showed an
overhang above this joint, amounting in one or two cases to as much as ½
in., due to the fact that the bench-wall form moved or did not fit
tightly. This defect was obviated by building the foundations with an
offset on the face, shown by Fig. 13, _B_, so that the joint came at the
level of the top of the flagging over the ditches, and therefore was
almost entirely concealed; at the same time this allowed a sufficient
surface, on the plane of the face of the bench-wall, against which the
bench-wall forms could be braced and lined up.

  [Illustration: Fig. 13.
  PLAN SHOWING VARIOUS METHODS OF BUILDING FLOOR AND FOUNDATION,
  AND DETAILS OF FORMS]

The ditch forms were set very carefully to line and grade by the
alignment corps, as this formed the starting point of all the rest of
the work, the only other thing which was necessary was to give a level
at the front end of the bench-wall form, after it was set, for the
elevation of the top of the bench, and to check up the stations of the
ends of the sections occasionally to see that they were at the even
25-ft. points (that is +08, +33, +58, and +83).

After a short length had been built with the ditches only, it was
thought desirable to try and put in the floor as well, so that the whole
of the concrete would be put in place as the lining advanced, and leave
less cleaning up to be done over the end of a single track, in the
restricted spaces between the bench-walls. Fig. 13, _C_, shows the
method finally adopted. In this may be seen the three stages in which it
was put in, the details of the ditch forms being shown by Fig. 13, _D_.

In that part of the tunnel where sand-walls were built, a hollow tile
drain was built into the foundation, as shown in Fig. 13, _A_ and _B_,
along the foot of the water-proofing and connected at intervals with the
drains by 4-in. cast-iron pipes. When the sand-walls and water-proofing
were not built, however, the concrete of the foundations was sloped from
the neat line back to the rock, as shown by Fig. 13, _C_3, so that in
case any water found its way down through the rock packing, its tendency
would be to flow back against the rock, or to follow the low part of
this concrete to 4-in. cast-iron pipes leading to the side ditches,
rather than to find its way through the joint between the foundation and
the bench-wall and so into the lower duct lines.


_Sand-Walls._--The sand-wall forms first used are shown in Fig. 2, Plate
XXIV, with a section of the finished sand-wall. As this work was only
intended to give a comparatively smooth surface against which to place
the water-proofing, no particular care was taken with the surface,
except to avoid sharp projections which might cut through the felt and
pitch used for this purpose. A rather porous concrete (with all the rock
which could be safely embedded in it and have the wall stand) was used,
so that it would not act as a dam, but rather tend to allow the water to
find its way to the bottom of the tunnel, and so into the drains.

The traveling gantry for placing the concrete in the sand-walls, as
first designed, with the belt conveyor, could of course only deliver the
concrete at one end. Before setting the forms for a new section, it was
necessary, therefore, to move the gantry ahead, before the cross-bracing
between the tops of the forms, which also held the top platform, could
be placed in position. Fig. 2, Plate XXIV, shows the end of the conveyor
over the top of the cross-braces. In order to hold the bottom of these
forms, small wooden blocks were embedded in the foundation concrete,
against which they could be wedged, as shown by Fig. 13, _A_; these
blocks were cut out after the sand-wall had been built.

After the forms had been filled, the conveyor could not be moved back to
the bench-wall until the concrete had set sufficiently so that these
cross-braces could be removed, and, on account of the overhang at the
top, the set had to be fairly good in order to prevent this overhang
from breaking off. This arrangement, therefore, for placing the concrete
was found to be impractical, if the proposed schedule of a section of
bench-wall and a section of sand-wall to be built on alternate days, was
to be carried out. In a few instances, where the sand-wall was finished
fairly early in the afternoon, the forms were released next morning, and
the conveyor was moved back, but, even then, 2 or 3 hours at least were
lost at the beginning of the shift. The conveyor, however, was
abandoned, for the reasons previously given, and the traveling gantry
was rearranged to allow concrete to be delivered at either end; it was
then only necessary to move it backward and forward between the bench-
and sand-wall forms instead of through these forms. This permitted the
construction of the much more substantial type of forms shown by Fig.
14.

After being moved ahead on the track on top of the foundation, the form
was first blocked up to grade, and then adjusted to line by the screws
and slotted cleats shown at _B_, Fig. 14, after which it was secured by
the braces from the ditches, as shown. The face lagging was placed in
separate pieces and held against the uprights by lightly nailing every
third or fourth piece; the whole was removed each time the form was
moved, and built up again as the concrete was placed.

Considerable care was taken to slope the top of the sand-wall back
toward the rock, as shown by Fig. 14, and to allow free drainage along
the top (which ran parallel to the grade of the tunnel) to the 4-in.
cast-iron drain pipes which carried the water from the rock packing
above the arch to the drains beneath the track.

Sand-walls were built for a length of about 1,100 ft. in each tunnel at
the Weehawken end, and about 700 ft. in each tunnel at the western end,
the remainder of the work, with the exception of a few short stretches,
not being considered wet enough to require water-proofing.


  [Illustration: Fig. 14.
  TRAVELING FORM FOR BUILDING SAND-WALL;
  DETAIL SHOWING METHOD OF HANGING WATER-PROOFING FROM TOP OF SAND-WALL]

_Conduits._--The arrangement of the conduit lines is shown in the
general cross-section.[3] On the core-wall side there are 48 lines for
telegraph and telephone cables, built of 4-way multiple conduit, each
piece of which is 3 ft. long and about 10 in. square outside. On the
other side there are the high- and low-tension lines, built of single
conduit 18 in. long and a little more than 5 in. square outside.
Manholes or splicing chambers are built every 400 ft., and are about
8 ft. long and 4 ft. wide. General views of the conduits as built are
shown in Fig. 4, Plate XXV, which shows all the lines in one tunnel, and
in Fig. 1, Plate XXV, which shows the telegraph and telephone lines,
with the expanding mandrels used in laying them.

    [Footnote 3: Plate VIII in the paper by Mr. Jacobs.]

  [Illustration: Plate XXV.
  Fig. 1: K 173. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels.) Hackensack Portal and Approach. Telephone and Telegraph
  ducts and mandrels. Nov. 20, 08.
  Fig. 2: K 125. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels) Weehawken Shaft, North Tunnel. View showing general
  construction of tunnel lining forms, and clearance to allow disposal
  of excavated material. June 17, 07.
  Fig. 3: K 156. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels) Weehawken Shaft, South Tunnel. North side looking East,
  showing method of placing waterproofing. Oct. 22, 07.
  Fig. 4: K 147. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels) Weehawken. General view showing center and first section of
  arch and completed lining, North Tunnel. Sept. 24, 07.]

In attempting to plan the work of placing the lining, two methods of
building the bench-wall were considered. One was to build the wall in
longitudinal sections, each section separated by a line of ducts; and
the other was to attempt to build the wall in the manner called for by
the specifications, which required the concrete to be carried up in
layers as the conduits were laid. In this latter method, it was proposed
to bond the concrete together with the forked bonds, the details of
which are shown by Fig. 15, _A_, but, as it might have been impractical
to use these if the wall had been built in sections, provision was made
in the contract to place expanded metal, as shown by Fig. 15, _B_, if
this was thought advisable. The method of construction necessary, if the
wall had been built in sections, is shown graphically by the five
sketches, Fig. 15, _B_, 1, 2, 3, 4, and 5.

The form and details of the expanding mandrel which was finally designed
to meet the conditions, and proved so satisfactory in every way, are
shown by Fig. 15, _C_. The mandrel consisted of two triangular pieces of
hard pine, separated by wedges attached to one piece which fitted into
slots in the other; these, when expanded, practically filled the whole
of the inside of the ducts. One of these mandrels was placed in each
line of single ducts and two in each 4-way duct, placed diagonally, as
shown in Fig. 1, Plate XXV. This required 60 mandrels at each working
point, or 240 for the whole work. The mandrels were 35 ft. long, so that
they easily covered the whole of a 25-ft. section, projected
sufficiently far back into the previously finished work to assure the
continuity of the alignment, and allowed the ends to be racked out at
the forward end to secure proper breaks between the joints.

In laying the single conduits, as a rule, the (collapsed) mandrels were
pulled ahead from the previous section as each line was laid, and the
conduits were strung on it until the whole length was completed; the
conduits were then pushed up tight together, so as to close the joints
as tightly as possible, and then the mandrel was expanded. The conduits
were thus held firmly in position, and the forward end of the line was
lifted slightly so that the wraps could be placed around the joints. The
4-way conduits were generally laid in the ordinary way, except that no
laying mandrel was necessary. One dowel was used between each of the
pieces of conduit, at the center, and the joints were wrapped. When a
line was finished, two mandrels were placed diagonally in each line and
expanded simultaneously, so that any inequalities in the ducts
themselves were divided as far as possible. In connection with the use
of these mandrels, one of the points which was most carefully watched
was that they projected back into the last completed section, thus
insuring the continuity of the alignment.

It was originally intended to wrap the joints of the 4-way ducts only,
but it was found to be impractical to keep the grout from the wet
concrete entirely out of the single ducts, and, after a short trial, it
was decided to wrap these also. The expanding mandrel kept out a great
deal of the cement, and, in the sections laid without wraps, the only
difficulty from this cause seemed to be that a slight film of grout,
from 1/16 to ⅛ in. thick, was deposited on the bottom of the inside of
the ducts at some places, and although this was not considered a serious
defect, it was thought that the slight extra cost of placing the wraps
would undoubtedly be justified by the practically perfect results
obtained by using them.

Considerable attention was given to breaking the joints of the ducts
properly, so as to maintain throughout the conduit lines the greatest
break possible. The joints in each superimposed line were broken at half
the length of the individual pieces of conduit, the joints in lines in
the same horizontal plane being broken at one-quarter the length, thus
preventing any joints from touching one another either at the sides or
corners, which tended to prevent a burn-out on one line from being
communicated to another. There was some little difficulty at first in
maintaining the breaks, owing to slight variations in the lengths of the
conduit, but after a very short time both the workmen and the inspectors
became very expert at this and in the proper use of short lengths to
maintain the spacing; after the first few weeks there was little if any
difficulty in attaining at all times almost perfect results. The method
of making the breaks is shown in the photographs and by the isometric
sketch at _F_, Fig. 15.

All the conduits used on this work were furnished by the Great Eastern
Clay Company, and were made at its factory at South River, N.J., where
they were inspected before shipment.

The mandrel used in the final rodding was made as shown at _G_, Fig. 15,
the larger size being used for all lines. The rods for pushing it
through the conduit lines were made of 6½-ft. lengths of ordinary 1-in.
wrought-iron pipe with extra long (3-in.) couplings. The lines were
rodded in both directions from alternate manholes, thus avoiding
uncoupling the rods and allowing every pull to be effective in pushing
the mandrel through the ducts.

  [Illustration: Fig. 15. [Full Page]
  ELECTRICAL CONDUITS: METHODS OF LAYING, RODDING, ETC.
    A. FORK ENDED STEEL BONDS FOR CONDUITS.
    B. SEQUENCE OF METHODS OF BUILDING BENCH-WALL PROPOSED WHEN USING
        EXPANDED METAL BONDS.
    C. ISOMETRIC DRAWING OF EXPANDING MANDREL.
    D. DETAILS OF “WEASEL” Used for gripping disconnected pipe rods in
        conduit
    E. CUTTER FOR REMOVING OBSTRUCTIONS IN CONDUITS.
    F. ISOMETRIC SKETCH SHOWING METHOD OF BREAKING JOINTS AND POSITION
        FORKED BONDS.
    G. PLAN AND SECTIONS OF EXPANDING MANDREL.

   INDEX
  +-----+------------+-------------+
  |     | Multi-Duct | Single-Duct |
  |     | Mandrel    | Mandrel     |
  +-----+------------+-------------+
  | _A_ |   3¼”      |   3⅜”       |
  | _B_ |    ¾”      |    ⅞”       |
  | _C_ |   2½”      |   2⅝”       |
  +-----+------------+-------------+

  Note

  End pipe connections may be changed to suit connections of rodding
  outfit, care being taken to use a connection which will not split and
  expand the mandrel if it should be driven back into it, in attempting
  to ram the mandrel back when stuck in a duct.

  Connection at Head End may be dispensed with, if the mandrel is
  threaded through ducts by rods attached to the trailing end.]

Wooden rods were used at first, but proved entirely too light, as the
mandrels used were a close fit, and it required considerable effort to
push them through 400 ft. of conduit. Iron pipe with ordinary couplings
was next tried, but the couplings broke quite often, as the threads
became worn in uncoupling the sections to move the rods from one line to
another, and the break was generally inside a duct line. The long
couplings were finally adopted, and a set of rods was put in each line,
that is, six sets in all, so that when coupled up they remained in the
line until it was finished. The expense of the extra quantity of pipe
thus required was more than offset by the decreased labor cost.

It was thought necessary at first to run a cutter, Fig. 15, _E_, through
the conduits ahead of the final rodding mandrel, but this was soon found
to be unnecessary except in a very few instances, and, after a short
experience, the cutter was only used at places where an obstruction was
encountered by the mandrel.

At such times as the pipe became uncoupled inside the duct line, the
part remaining inside was recovered by the use of the tool shown at _D_,
Fig. 15, called a “weasel.” In two instances, the mandrel became stuck
in such a manner that the duct line had to be cut into in order to take
it out.

The best day’s work of the rodding gang (1 foreman and 4 men) was 20,400
duct ft. of the 4-way conduit in the telegraph and telephone line, and
19,200 duct ft. of single conduit on the low-tension line, an average
day’s work under ordinary conditions being about 10,000 duct ft. The
cost, including labor, material, and all tools, for rodding for the
whole work was slightly less than 0.2 cent per duct ft. The average cost
of the single conduit was about 0.25 cents per ft., and of the 4-way,
0.15 cents per ft. About 10% of the conduit lines were rodded twice,
owing to partial sections having been rodded once before completion. The
best continuous work on rodding was done between October 22d and 29th,
1908, when in 7 working days, 105,600 duct ft. were rodded, an average
of a little more than 15,000 ft. per day.


_Bench-walls._--The original design for the tunnels provided for the
construction of a brick arch above a point 22° above the springing line,
that is, the part above the side-walls (Fig. 10). It was thought
desirable, therefore, in designing the bench-wall forms, to provide for
placing the concrete in the side-walls and bench-walls at one operation.
These forms, as first designed, are shown by Fig. 2, Plate XXV, and the
details in Fig. 16, _A_ and _A’_; they were built of steel, the facing
plates being 5/16 in. thick, in pieces 4 ft. 6 in. wide, and in length
about 6 in. more than the height of the bench-wall.

  [Illustration: Fig. 16. [Full Page]
  DETAILS OF TRAVELING FORMS USED IN THE CONSTRUCTION OF THE BENCH WALLS
    A’. CROSS-SECTION OF STEEL FORM
    A. LONGITUDINAL SECTION AND ELEVATION OF STEEL FORM USED AT
        WEEHAWKEN END
    B. DETAILS OF SCREW-JACKS FOR ADJUSTING FORM TO LINE
    C. SECTION _C_-_D_ SHOWING CONNECTION OF FACE PLATES TO I-BEAM
        UPRIGHTS
    D. DETAILS OF WOODEN FORMS USED AT WESTERN END: CROSS-SECTION,
        PART LONGITUDINAL SECTION
    No chutes were used with these forms, the wheel-barrows being dumped
      from the runways on the sides.]

The design was controlled very largely by the necessity of providing the
requisite clearance for the locomotives and muck cars, and the principal
feature was the support of the forms on two trusses, one at either side,
the front ends of which were supported from the foundation on a long
leg, as shown in Fig. 3, Plate XXV, and the rear ends directly on the
journal-boxes of wheels traveling on a rail on the top of the finished
bench, as shown in Fig. 2, Plate XXV.

Although it had been decided to substitute concrete for brick in the
arch before any of the lining was actually placed, two sets of forms for
the Weehawken end had already been ordered and delivered, so it was
decided to use them as designed, and place the side-wall with the bench.

The forms were designed so that 30-ft. lengths could be built, and this
was done at the start, but owing to the occurrence of the refuge niches,
ladders, etc., at 25-ft. intervals, it was soon seen that it would be
advisable to build the bench-wall in sections of that length (25 ft.),
or multiples of it, and as the clearance conditions seemed to preclude
the possibility of making the forms 50 ft. long, 25 ft. was adopted.
This permitted the removal of one of the panels, 4 ft. 6 in. wide, and
at the same time it was decided to remove the side-wall forms. This
decreased the load on the trusses considerably, but being still a trifle
weak, they were strengthened by the substitution of 1¼-in. truss rods
instead of the ¾-in. rods used originally. The top platform and the
cross-bracing were also stiffened a little and tightened up to prevent
racking.

The construction of the side-walls in conjunction with the bench-wall
was abandoned for three reasons: First, it was found that there would be
a much more even distribution of the work by including the side-wall
with the arch rather than with the bench; second, there was difficulty
in getting a good finish for the top of the bench-wall, as of course a
top form for the latter had to be placed to prevent the concrete from
squeezing up when the side-wall was built above it, which prevented
troweling; the third reason was the weakness of the whole form as
designed, and the increasing difficulty of adjusting it to line as the
work progressed, the principal difficulty being with the curved
side-wall forms.

The bench-wall forms were set in position, after they had been moved
ahead, by first blocking the bottom against the face of the foundation,
as shown by Fig. 13. As previously noted, this foundation face had been
built very carefully to line. The back end of the form, of course, was
blocked tightly against the end of the previously finished section, and
the top was made plumb by the adjusting screwjacks shown in Fig. 16,
_B_. At first these screws were ¾-in., but they were afterward changed
to 1¼-in. The only points which it was necessary for the alignment corps
to give in setting these forms was a grade at each of the front ends for
the top of the finished bench.

The steel face forms in both tunnels gave excellent results, as far as
smoothness of finish was concerned, but, owing to the imperviousness of
the steel, small air holes were formed in the surface, though not in
sufficient numbers or size to cause trouble or disfigure the work in any
way.

The design of the bench-wall forms used at the western end, where this
differs from the steel form, is shown by Fig. 16, _D_. The principal
features in which they differed from those used at the Weehawken end was
in the substitution of 2½-in. tongued and grooved hard pine for the
face. This timber was of the very best quality obtainable, each piece
being especially selected and as nearly clear and free from knots or
other defects as it was possible to get it. The edges of each piece were
planed at the back so as to insure a tight joint on the face, and all
joints were shellacked. These forms were used, without renewal of the
face timber and with only two planings, for a length of 2,500 ft., or
100 separate sections, and gave good satisfaction.

In order to obtain a surface to which the face lagging could be
fastened, wooden uprights were used and were reinforced on either side
by light channels bolted together through the timber, in place of the
=I=-beams used on the steel forms. The lagging was nailed to these
uprights by 6-in. wire nails driven through the top edges of each piece
as it was placed in position, thus leaving the surface entirely clear
and free from any marks or nail holes, and in condition for planing when
this became necessary. Runways for wheeling the concrete were built one
either side over the bench-walls instead of having a center platform
with chutes, as was used at Weehawken.

When the original lagging had become too much worn for further use, it
was resurfaced with strips of ⅞ by 2½-in., clear, tongued and grooved,
hard pine, placed vertically, which did fairly well and lasted to the
end (about 1,000 ft.), although it was not altogether satisfactory, and
the last eight or ten sections built had to be rubbed down with a wooden
float in order to obtain a suitable finish.

In designing the forms for all exposed surfaces in the tunnels, it was
the desire of the contractors to obtain directly from them a surface
which would be satisfactory to the engineers without further finishing
than the patching of minor defects. In this they were generally quite
successful, and excellent results were obtained, as shown in the view of
the finished tunnel, Fig. 2, Plate XXVII. The surface of the bench-walls
was obtained solely by spading the face with a flat spade as the work
progressed. No after treatment was resorted to, except for the few
sections where the forms became worn. The top of the bench-wall was
finished with a float about 2 or 3 hours after the concrete was placed.

When the work was well organized, a bench-wall was built at each end
each day, one day in the North Tunnel, and the following day in the
South. During the time sand-walls were being built, a sand-wall and
bench-wall were built on alternate days in each tunnel, care being taken
that when a bench-wall was being built in one tunnel, the sand-wall was
being built in the other, this being necessary in order to equalize the
work of the night gang and the conduit layers as well as the
transportation.

The conduit layers on the day shift, two or three men and a foreman,
required about 2 hours in the forenoon and 1 hour in the afternoon to
lay their portion of the conduits, and usually finished this work by 3
P.M. At other times during the shift they were utilized at those points
where rock packing was heaviest, and when the packing was brought in in
the large cars, as shown in Fig. 1, Plate XXVI, these men helped unload
it so that the track could be cleared as soon as possible. When
water-proofing was to be done, the number of men in this gang was
increased, so as to enable them to do that work also.

  [Illustration: Plate XXVI.
  Fig. 1: K 167. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels.) View of form for circuit breaker chamber at Sta. 286, and
  travelling gantry for placing concrete in arches, looking Easterly
  from near Sta. 280+85, South Tunnel. Oct. 3, 08.
  Fig. 2: K 166. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels.) View of forms for storage chamber at Sta. 294+24, looking
  Southward. Sept. 17, 08.
  Fig. 3: K 163. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels.) Tunnel lining. Rock packing over arches, South tunnel Sta.
  ???+?? end of completed section. May 19, 08.
  Fig. 4: K 168. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels.) Showing method of waterproofing in timbered tunnel section
  at Weehawken end. Oct. 21, 08.]

A gang of four rough carpenters and a foreman was employed on the day
shift; they moved and set the bench-wall forms or sand-wall forms, as
the case might be, and moved the traveling gantry into position. This
was done in the afternoon, and required about 3 hours. They also took
out, cleaned, repaired, and set all ditch forms, all passenger forms,
circuit-breaker forms, and did all other repair work. The ladder forms,
the refuge-niche forms, and overhead conductor pocket forms were
attended to by one man, who set, removed, cleaned, and repaired them.
The carpenters on the night shift set the arch centers and gantries,
also the manhole forms when needed. The conduit layers on the night
shift laid up half the 4-way conduits (3-high) and one-third of the
single ducts (4-high). This one gang laid the conduits in two sections
of bench-wall each night, that is, one section at Weehawken and the
other at the western end.

In concreting the bench-walls, the concrete was first placed on the side
containing the single conduit until it reached the top of the four tiers
laid, then the concrete gang was turned over to the side with the 4-way
conduits while four more tiers of single conduits were laid, the work
thus progressing, the conduits being laid on one side while concrete was
placed on the other. On the side of the 4-way conduits the concrete was
built in two layers while that on the side of the single ducts was built
in three; the interval between the different layers was not sufficiently
long to prevent a complete bond being obtained, and there were only one
or two instances where there was any mark on the face to indicate a
break.

After the work had been in progress some time, it was found to be quite
feasible to build all the 4-way conduits at night and half the single
conduits, that is, 6 ducts high, as the mandrels proved amply sufficient
to hold them in place; in fact, had it been necessary, the writer has no
doubt that all the ducts might have been laid and held in place with
very little extra precaution, by the use of the expanding mandrels,
as described under the head of conduit laying. A =V=-shaped joint about
½ in. deep was made between each section of bench-wall so that the
expansion cracks would follow this joint rather than show irregularly on
the face. These joints divided the face into the even 25-ft. panels, and
were very effectual in concealing what few cracks there were.

After the construction of the sand-walls was discontinued, the space
behind the bench-walls, between the neat line and the rock, was filled
with rock packing, which was generally built, part way up at least, as a
dry wall ahead of the construction of the bench-wall, or it was put in
place simultaneously with the concrete, care being taken to keep it as
free as possible for the drainage of any water there might be. Toward
the latter part of the work, owing to the difficulty of getting
sufficient rock packing during the day, a rough back form for the
bench-wall was built at the neat line, in places where the section was
at all large, and the space was filled with rock afterward, generally at
night or on Sundays.

In the sections where water-proofing was required, where no sand-wall
was built, the rock was taken out for 2 ft. outside the neat line,
if the excavation was not already that far out (at the expense of the
contractors, who preferred to do this rather than build the sand-walls
for the short sections required), so that there would be sufficient room
for placing the water-proofing on the back of the bench-walls, as shown
by Fig. 18, _E_. The water-proofing of these sections was left until
just before the arch was to be built, and after being placed it was
protected by a single row of brick laid on edge before the rock packing
was filled in.


_Arches._--The centering used for the arches is shown very clearly in
Fig. 4, Plate XXV, which is a view of the back end of the first section
built at Weehawken. In this part of the tunnel, the lower part of the
arch, about 5 ft. above the bench-wall, was built first, as previously
referred to, but the centers, as will be seen, were built so that they
could be used for the whole of the arch. The forward bulkhead, and the
shoveling platform on a section being built, are shown in Fig. 3, Plate
XXVI.

The front bulkheads used were made in nine sections, bolted to a 2½ by
2½-in. angle bent to the radius of the arch, as shown in Fig. 3, Plate
XXVI, and fitting on the end of the lagging; when set they were braced
partly against the rock of the roof and partly against the gantry. After
the ribs and part of the lagging had been set by the night gang for a
fresh section of arch, the braces holding the bulkheads were knocked
out, the concrete placed during the day having set sufficiently by this
time; the whole of the bulkhead was then easily moved ahead, sliding
along the lagging to the forward end, and made ready for the next day’s
work. The middle section at the top was taken out temporarily, to
facilitate working at the sides, until it was needed.

The traveling gantry used in handling the concrete for the arch is shown
in Fig. 1, Plate XXVI, which also shows the form for the circuit-breaker
chamber, and a car of rock packing on the track beneath.

The arches were built in 10-ft. sections, the ribs being spaced 5 ft.
apart, the end ribs of each section supporting the end of the lagging on
two adjoining sections. Five sets of lagging and ten ribs were used at
each place where the arch was being built, thus giving each section
practically 4 days’ set before removing the centers. Probably in the
greater part of the work the centers could have been removed in from 40
to 48 hours after the concrete had been placed, but 3 days was
considered the least time which would certainly be safe at all times,
and the contractors thought that the very slight additional expense
involved in leaving the centers up 4 days was more than warranted by the
additional feeling of security.

The lagging was made from 3 by 6-in. clear, hard pine, 10 ft. long,
dressed to about 2½ in. in thickness, about 5½ in. in width, and the
sides to radial lines. As it was placed, every third or fourth piece was
lightly nailed to the ribs; when the latter were released and taken
down, the nails pulled out, and the lagging was left in place until one
piece was pried out, allowing the others to fall. A light =A=-frame,
about 8 ft. long, spanning the bench-walls, was placed below, in order
to break the fall and allow the lagging to slide to the top of the
bench-walls rather than fall to the track beneath.

Cross-passages between the two tunnels were built every 300 ft., their
form being shown on Plate VIII of the paper by Mr. Jacobs. There were
two circuit-breaker chambers, one at Station 286 and the other at
Station 310. Steel doors are provided so that all the openings between
the two tunnels can be closed. At Station 294+24, the core-wall broke
through for a length of about 40 ft., and instead of filling this in,
a storage chamber 34 ft. long and 11 ft. wide, inside, was built there,
the form for which is shown in Fig. 2, Plate XXVI. This photograph, as
well as Fig. 1, Plate XXVI, a form for a circuit-breaker chamber, shows
the method of setting the steel doors in the forms, so that they were
built into the concrete instead of being fastened in with expansion
bolts afterward, thus showing a perfect fit and a much neater job.

During construction the arches in each tunnel were kept even with each
other, so that when the cross-passages were reached, they, and the
sections of arch which they joined, could be completed at one operation.

By the methods used on this work, one section of arch was easily built
in a shift, so that the monolithic construction of each section was
easily secured, and concrete, as wet as it was possible to handle with
shovels, could be used for all except the last 5 ft. or so at the top,
thus getting a structure which was as nearly impervious as possible
under the circumstances.

The gangs placing the arches were paid over-time when they were required
to work after 6 o’clock to finish their section, which was generally
only necessary when the quantity of rock packing to be placed was very
large. If they finished their section before 6 o’clock, however, they
were allowed to quit when this was done, and were given a full day’s
pay. The difference in time, when there was any, was usually due to the
greater or less quantity of rock packing, as the excavation varied from
the standard section line.

In building the arches, the night gang set the two ribs (one at the
center and one at the forward end of the section to be built), placed
the lagging on the sides, 4 or 5 ft. high, built the shoveling platform
on the horizontal cross-braces of the ribs, and placed the traveling
gantry in position for use. The forward end of the gantry (that is, the
end farthest from the arch being built), as shown in Fig. 1, Plate XXVI,
was loaded with rock packing to be used as required. As the concrete was
brought into the tunnel it was hoisted and dumped on the end of the
gantry next the arch, and shoveled from there to the platform on the
ribs and from there into place. The rock packing brought in during the
day was dumped on the front or back end of the gantry, as was most
convenient, and handled into the work in the intervals between batches
of concrete. The concrete and rock packing, with the back-lagging and
water-proofing, where these were used, were placed simultaneously, or
nearly so, and brought up the sides together until the key was reached;
the latter was then worked from the back toward the front. The key was
usually made about 5 ft. wide, the lagging for this width was made 5 ft.
long and put up in two sections. It was found to be more convenient to
have the key of this width than narrower.

The method used in making the closures where two sections of the arch
came together is shown by Fig. 17.

  [Illustration: Fig. 17. [Full Page]
  SKETCH SHOWING METHOD OF MAKING ARCH CLOSURE
    CROSS-SECTION OF TUNNEL SHOWING JACK PARTLY EXTENDED
    LONGITUDINAL SECTION OF TUNNEL SHOWING JACK PARTLY EXTENDED
    PLAN OF BOX; END VIEW
    PLAN OF PLUNGER, BOTTOM OF BOX; END VIEW OF PLUNGER,
        JACK FULLY EXTENDED]


_Water-proofing._--As already pointed out, the original design for the
lining of these tunnels provided for a brick arch. It was intended to
cover this arch with water-proofing, this latter extending over the
whole of the roof and down the sides as far as the bottom of the conduit
lines. The water-proofing was to be placed against the sand-walls on the
sides, up to the top of the side walls, Figs. 10 and 14. Over the arch,
after being placed, it was to be protected by an armor course of brick,
laid flat, the space between the brick and the excavation, which was
required to be not less than 4 in. (and, as a matter of fact, was
actually a great deal more), being filled with rock packing. Besides
filling the space, this latter was designed to allow any water from the
roof of the tunnel to find its way easily to the top of the sand-wall,
from there being carried through the 4-in. cast-iron pipes, shown on
Plate VIII[4] to the side ditches in the floor of the tunnel.

    [Footnote 4: Of the paper by Mr. Jacobs.]

All the water-proofing placed in these tunnels was of felt and pitch,
six-ply felt and seven layers of pitch. The felt was required to be
Hydrex, or of equal quality, and the pitch, “Straight run coal-tar pitch
which will soften at 60° Fahr., of a grade in which the distillate oils
will have a specific gravity of 1.05.”

In addition to tests as to the above qualities, the pitch was analyzed
to determine the amount of free carbon it contained, and was not
accepted if this fell below 20 per cent.

It was considered quite important that there should be absolutely free
drainage on the outer side of the lining, so that there would be no
chance for any water to acquire a head. More than three-quarters of the
length of these tunnels is below the level of mean high water, and while
it was hardly expected that there would be any direct connection between
the water in the Hudson River and the groundwater of the section
penetrated, it was thought wise to provide ample drainage.

Before the lining was started, however, the excavation had progressed
sufficiently to show that the tunnels, while very wet in places, and
varying from that to quite damp, would be, on the whole, much dryer than
had been anticipated. It was then decided to substitute concrete for the
brick in the arch and omit the water-proofing over the top, except at
places where water came into the tunnels in sufficiently large
quantities to form practically a continuous stream. Three general types
of construction for the arch were decided on, as shown in Fig. 18. The
first, as shown at _A_, was to be used where the tunnel was quite dry.
In this type, the sand-wall was omitted entirely, and the concrete and
rock packing were built up together, the rock packing impinging to a
certain extent on the concrete, and the concrete squeezing somewhat into
the rock packing, as shown by Fig. 4, Plate XXV. The section shown at
_B_ was used where the tunnels were damp, or where there were slight
droppers not forming a continuous stream. The back lagging, of 1-in.
boards, which was left in place, provided a practically smooth outer
surface on the concrete arch, and allowing the concrete and rock packing
to be built almost simultaneously. It was considered that the free
drainage through the rock packing, the surface of the boards, and the
smooth outer surface of the concrete in the arch would allow the
comparatively small quantity of water in these parts of the tunnel to
find its way to the sides, and thence to the ditches at the bottom,
rather than to percolate through the concrete, and this proved to be
very generally the case, as is shown by the dry condition of the tunnel
as built. The back lagging was used over the arch, both where the
sand-wall was built and where it was omitted, as well as being placed
over the water-proofing of the arch as an armor course where
water-proofing was required. Where the sand-walls were built and
water-proofed, and where the water-proofing was not carried over the
arch, the water-proofing was turned in at the top, as shown at _C_, Fig.
18.

  [Illustration: Fig. 18. [Full Page]
  VARIOUS TYPES OF ARCHES, AND WATER-PROOFING USED
    Method of Lapping Mats over Arch
    Method of making joint when work on section was not continuous. Part
      of joint on radial line, part sloping slightly toward outside of
      arch.
    DETAILS OF WATER-PROOFING
    One layer of felt with 4" overlap to be nailed to lagging of inch
      boards, using tin washers on nails over the whole of the intrados
      of the arch before starting any concrete or placing any of the
      permanent felt and pitch water-proofing. The water-proofing over
      the arch can be laid in mats of three thicknesses of felt properly
      joined together with pitch made as shown diagrammatically at “_x_”
    Each of these mats of three-ply felt will be overlapped half the
      width of the mat, as shown diagrammatically at “_y_”]

The third method provided for water-proofing the whole of the arch, and
was the same as _B_ except for the addition of the water-proofing inside
the back lagging. In placing this water-proofing, the felt was cut in
strips about 11 ft. long (about 1 ft. longer than the length of a
section of arch), and six thicknesses were cemented together with hot
pitch. These mats were then laid shingle-fashion, as shown at _D_, Fig.
18, up the sides of the arch until a space about 5 ft. wide remained at
the crown; shorter mats were then brought out over this, laying them
perpendicular to the axis of the tunnel. Care was taken in making all
laps, irrespective of the direction in which the arch was built, so that
they would lay with the grade, that is, so that the water would tend to
flow over the edges of the laps rather than against them.

Most of the wet sections of the tunnel were at the ends, where
sand-walls had been built for the purpose of providing a smooth surface
against which the water-proofing was to be placed; there were several
wet places at isolated points in the tunnels, however, and, in order to
avoid building sand-walls at these points, the method shown at _E_, Fig.
18, was adopted. This involved a slightly larger excavation, 2 ft.
outside of the neat line, up to the height of the top of the bench,
where there was not already that much room. The bench-wall was built
with a back form on the neat line, the water-proofing was placed as
shown, protected by an armor course of brick, and then continued over
the arch when this latter was built. The excavation and refilling with
rock packing were done at the contractor’s expense, which he was willing
to assume rather than build these short sections of sand-wall.

  [Illustration: Plate XXVII.
  Fig. 1: K 181. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels.) Timbered section near Weehawken Shaft, showing method of
  placing waterproofing and keying arch. Dec. 8, 08.
  Fig. 2: K 184. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels). View of completed tunnel looking Eastward from Sta.
  323+60. South Tunnel. Feb. 8, 09.
  Fig. 3: K 149. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels) Hackensack Portal, general view of completed Portal, and
  arches through cut and cover section looking East. Oct. 15, 07.
  Fig. 4: K 190. P.R.R. Tunnels, N. R. Div. Sect. K. (Bergen Hill
  Tunnels.) Hackensack Approach. General view, looking East. March 16,
  09.]

The method of water-proofing that part of the timbered section which was
very wet, is shown at _F_, Fig. 18, and in Fig. 4, Plate XXVI, and
Fig. 1, Plate XXVII. A lagging of 1-in. boards was nailed up the sides
and to the soffit of the segmental timbering, all the spaces outside of
this lagging being carefully filled with rock packing. Before starting
any concrete work, a single thickness of water-proofing felt was nailed
to the inner side of the lagging, which not only served to protect the
finished surfaces of the concrete from the water which fell copiously
from the roof, but also provided a comparatively dry surface to which
the regular six-ply water-proofing could be cemented with pitch and held
in position, while the concrete was placed against it.

In placing the water-proofing in this section on the sides, the strips
of felt were placed vertically, nailed at the top to the wall-plate, to
support their weight, and lapped and cemented with pitch to the sides as
on the sand-walls, except that there was no trouble from the overhang.
After the bench-wall had been built, the felt was cut just below the
nails and about 2 ft. above the top of the bench, so that the mats which
were placed over the arch could be inserted behind it. The roof was
covered with three-ply mats and lapped over a little more than half, as
shown diagrammatically on the drawing.

When the upper part of the arch was reached, where the cementing
strength of the pitch was not sufficient to hold the felt in place, the
mats were braced temporarily from the centering, as shown by Fig. 1,
Plate XXVII, until the concrete could be packed against it.

Where the water-proofing was placed against the sand-wall, the method of
securing the sheets at the top is shown in the small sketch on Fig. 14
and by Figs. 3 and 4, Plate XXIV. Fig. 3, Plate XXV, shows the laps of
the sheets and the method of hanging. At the start an attempt was made
to stick the water-proofing to the sand-wall, but this could not be done
on account of its dampness and the overhang at the top.

The sand-wall water-proofing was kept about 35 ft. ahead of the finished
bench-wall, as shown by Fig. 3, Plate XXV. As the bench-wall form was
moved ahead and set, the mat was braced back against the sand-wall from
the forms at a point just above the top of the finished bench, care
being taken to avoid wrinkles, as, if these were once formed, it was
practically impossible to straighten them out.

The completion of the bench-wall left the upper part of this
water-proofing stretched taut across the curved top of the sand-wall,
forming a chord of the arc. As the arch was built up, the top was
gradually slackened so as to allow the concrete to press the mat back
into place until the top of the sand-wall was reached, when the end was
turned in, as shown at _C_, Fig. 18, or the water-proofing was continued
over the arch, if that was necessary.

The desire to obtain a dry tunnel, and the methods adopted to secure it,
were responsible in a great measure for the decision to build the arch
in short lengths, as well as the reasons given under the head of arches.
Had the tunnels been dry throughout, the method shown at _A_, Fig. 18,
could have been used exclusively, and, except for the fact that
monolithic concrete might not have been obtained, there would have been
no objection to building longer lengths.

The quantity of water reaching the tunnel drains and flowing out of
their lower ends after the completion of the lining was about 100,000
gal. per day, or 75 gal. per min.; of this it is estimated that
considerably less than 1% comes through the lining in the form of leaks.
The very general distribution of this water over the roof is indicated
by the fact that, during the excavation of the first 1,000 ft. of both
tunnels from the Weehawken end, oilskins had to be provided for the
laborers to induce them to work at all. The success, therefore, of the
rock packing as a means of diverting this water to the side drains, is
shown, especially in view of the fact that, excluding the cut-and-cover
section, only 10% of the length of the arch, 1,189 ft., was
water-proofed.

Considerable care was taken to make all joints in the concrete which
were in such a position that water might follow through them to the
inside of the tunnel lining, in such a manner that they would slope
outward toward the rock. The top of the sand-wall is shown by Figs. 14
and 18. The slope of the back of the foundation may be noted in Fig. 18,
and the method of making the joint in the arch, in the few instances
where a section was not completed at one operation, is shown at _A_,
Fig. 18. These joints in the arch were not allowed to be made above a
point 60° above the springing line.


HACKENSACK PORTAL AND APPROACH.

The approach cut at the western end is 300 ft. long, the alignment being
a 2° curve, as shown in Fig. 19. The bench-walls and conduit lines built
throughout the length of the tunnels are extended through the approach
cut, the top of the former gradually sloping from the portal to the
mouth of the cut, where they are just level with the top of the rail,
the conduits also being depressed to the same relative position with the
tops of the benches.

  [Illustration: Fig. 19. [Full Page]
  BERGEN HILLS TUNNELS.
  Hackensack Portal and Approach.
  SECTIONS AND ELEVATIONS.
    PLAN OF APPROACH.
    PROFILE THROUGH APPROACH.
    SECTION SHOWING METHOD OF MAKING JOINT BETWEEN COPING AND WALL.
    PLAN SHOWING METHOD OF MAKING JOINT BETWEEN ADJOINING SECTIONS.
    SECTION OF BENCH AND RETAINING WALLS AND HALF ELEVATION OF PORTAL.]

The top of the rock at the mouth of the cut, Station 327, was from 4 to
6 ft. below the top of the rail, and gradually rose through the approach
until at the portal it was about 6 or 8 ft. above the roof of the
tunnel. The rock was covered with hardpan. A profile of this part of the
work is shown on Fig. 19. The rock throughout the approach was
water-bearing to a considerable extent, and a face-wall was built at the
sides with free drainage, through rock packing and vitrified and
cast-iron drains behind it, to keep this water from flowing over the
tops of the bench-walls, and also to keep the lines of conduits dry.

The retaining walls were built in 25-ft. sections, the joints
corresponding to those in the benches, being at the even stations, +08,
+33, +58, and +83. =V=-shaped joints were made down the face, and the
ends of the sections were made as shown by Fig. 19. The back part of the
joint was mopped with hot pitch before the next section was built, so
that there was practically no bond between any two adjoining sections.

The concrete in these walls was placed late in the season, and the
expansion cracks, which were entirely confined to the =V=-shaped joints,
were quite small even in the coldest weather of the following winter,
nor were there any indications during the past summer of any stresses
due to expansion. The coping and drain at the top of the wall were built
together, but separate from the rest of the wall, the joint being made
as shown in the sketch on Fig. 19. Thus far, there has seemed to be no
seepage through either the vertical or horizontal joints.

The portal is built of granite, a half elevation being shown on Fig. 19,
the stone being supplied by the Millstone Granite Company, Millstone
Point, Conn. Fig. 3, Plate XXVII, shows the portal and the cut-and-cover
section after the arches were completed but not covered.

The forms for the concrete in the approach were made of ordinary dressed
lumber, and the surface was rubbed twice after the forms were removed,
which was as soon as possible after the concrete had set. The surface
was first very lightly rubbed with a piece of soft, light-colored,
sandstone to remove any irregularities, being wetted slightly if
necessary while being rubbed. After the concrete had become fairly hard
and dry, it was rubbed a second time and a uniform texture and color
obtained. The completion of this work was delayed until the second week
in January, and considerable difficulty was encountered in obtaining a
good finish of that part which was built after cold weather set in, when
it was necessary to protect it from frost. Unless extreme care was taken
to prevent freezing after the rubbing, the entire surface was likely to
scale off, although no cement or other material was added to it after
the removal of the forms. A general view of the completed approach is
shown by Fig. 4, Plate XXVII.

  TABLE 6.

  ---------------------+----------------------+-----------------------+
                       |         DAY.         |         NIGHT.        |
         Title.        +-----+-------+--------+-----+-------+---------+
                       | No. | Rate. | Amount.| No. | Rate. | Amount. |
  ---------------------+-----+-------+--------+-----+-------+---------+
  Walking bosses       |   2 | $5.00 | $10.00 |     |       |         |
  Timekeeper           |   2 |  3.00 |   6.00 |     |       |         |
  Watchmen             |     |       |        |  5  | $2.00 |  $10.00 |
  Waterboys            |   1 |  1.50 |   1.50 |     |       |         |
  Carpenter foremen    |   2 |  3.50 |   7.00 |  1  |  4.00 |    4.00 |
  Carpenters           |  14 |  2.50 |  35.00 |  8  |  2.50 |   20.00 |
  Pipe-fitters         |   1 |  3.00 |   3.00 |     |       |         |
  Pipe-fitter’s helper |   1 |  1.75 |   1.75 |     |       |         |
  Wheelwright          |   1 |  2.75 |   2.75 |     |       |         |
  Wheelwright’s helper |   1 |  1.75 |   1.75 |     |       |         |
  Blacksmith           |   1 |  3.00 |   3.00 |     |       |         |
  Blacksmith’s helper  |   1 |  1.75 |   1.75 |     |       |         |
  Foremen riggers      |   1 |  3.00 |   3.00 |     |       |         |
  Riggers              |   6 |  1.75 |  10.50 |     |       |         |
  Foremen trackmen     |   1 |  3.00 |   3.00 |     |       |         |
  Trackmen             |   6 |  1.50 |   9.00 |     |       |         |
  Machinist            |   2 |  3.00 |   6.00 |     |       |         |
  Machinist’s helper   |   1 |  1.75 |   1.75 |     |       |         |
  Electrician          |   2 |  3.00 |   6.00 |  1  |  2.50 |    2.50 |
  Electrician’s helper |   1 |  1.75 |   1.75 |     |       |         |
  Lampman              |   1 |  1.50 |   1.50 |     |       |         |
  Pumpman              |   1 |  1.50 |   1.50 |     |       |         |
  Finishers            |   3 |  2.50 |   7.50 |     |       |         |
  Hoist engineers      |  12 |  3.00 |  36.00 |     |       |         |
  Dinky engineers      |   5 |  2.75 |  13.75 |  1  |  2.75 |    2.75 |
  Brakemen             |   5 |  1.75 |   8.75 |  1  |  1.75 |    1.75 |
  Switchmen            |   1 |  1.50 |   1.50 |     |       |         |
  Barnmen              |   1 |  2.00 |   2.00 |  1  |  2.50 |    2.50 |
  Drivers              |   9 |  1.50 |  13.50 |     |       |         |
  Foremen ductmen      |     |       |        |  2  |  2.50 |    2.50 |
  Ductmen              |     |       |        |  5  |  2.00 |   10.00 |
  Foremen laborers     |  13 |  3.50 |  45.50 |  2  |  3.50 |    7.00 |
  Laborers             | 120 |  1.75 | 210.00 | 20  |  1.75 |   35.00 |
  Compressor engineer  |   1 |  3.50 |   3.50 |  1  |  3.50 |    3.50 |
  Firemen              |   2 |  2.50 |   5.00 |  1  |  2.50 |    2.50 |
  Oiler                |   1 |  1.75 |   1.75 |     |       |         |
  Coal passers         |   2 |  1.75 |   3.50 |  1  |  1.75 |    1.75 |
  ---------------------+-----+-------+--------+-----+-------+---------+
        Totals         | 334 |       |$469.75 | 50  |       | $108.25 |

                         Total daily labor expense              $578.00
  ---------------------------------------------------------------------

The water finding its way into the side ditches in the approach, which
of course included all rain falling in this area, was intercepted just
inside the portal and carried back to the mouth of the cut through
24-in. cast-iron pipes laid beneath the conduits in the central
bench-wall, thus disposing by natural drainage of a not inconsiderable
quantity of water which would otherwise have flowed through the tunnels
to the sump at the Weehawken Shaft, from which it would have had to be
pumped to the surface.

About 100 ft. of the tunnel immediately east of the Hackensack Portal
was built by the cut-and-cover method, and the arch section used in the
tunnel was modified by widening the haunches, the thickness of the arch
at the crown being gradually increased from 22 in. at the portal,
Station 324, to 34 in. at Station 323, where the regular segmental
timbering at the tunnel commenced. A general view of the approach during
construction is shown by Fig. 1, Plate XXV.


CONTRACTOR’S ORGANIZATION.

Table 6 shows approximately the number of men employed daily on the
tunnel lining, by both the contractor and the sub-contractors, their
occupation, the average rate of wages and the total daily expense for
labor when the work was in full swing.


ENGINEERING ORGANIZATION.

The whole of the work of the North River Division was designed and
executed under the direction of Charles M. Jacobs, M. Am. Soc. C. E.,
Chief Engineer, and James Forgie, M. Am. Soc. C. E., Chief Assistant
Engineer, the construction of Section “K,” Bergen Hill Tunnels, being
directly in charge of the writer as Resident Engineer.

  [Transcriber’s Note:
  The two organizational charts, Figs. 20 and 21, have been reformatted
  for space.]

  [Chart: Fig. 20.

  PENNSYLVANIA TUNNEL AND TERMINAL RAILROAD COMPANY,
  SECTION “K”--BERGEN HILL TUNNELS.

  Organization of Staff of Resident Engineer.

  Organization Previous to the Holing Through of the Tunnels.

                      Resident Engineer.
                  _______________|________
                 |           |            |
             Assistant       |        Assistant
             Engineer.       |        Engineer.
       _________|________    |            |
       |                |    |            |
  Cost and Office  Field Inspection.  Alignment.
     Records.

  Cost and Office Records.
    Inspector.
    Two Clerks.
    Stenographer.
    Telephone Operator.
    Messenger.
    Janitors.

  Field Inspection.
    Weehawken.
      Chief Inspector.
        Inspector, N. Tunnel
            ”      S. Tunnel.
            ”      Mixer.
            ”      Excavation and Force Account.
        Inspector, Night.
        Cement Warehouseman.
          Conduit Inspector. (_one position_)
    Hackensack.
      Chief Inspector.
      Chief Inspector.
        Inspector, N. Tunnel
            ”      S. Tunnel.
            ”      Mixer.
            ”      Excavation and Force Account.
        Inspector, Night.
        Cement Warehouseman.
          Conduit Inspector. (_one position_)

  Alignment.
    Weehawken.
      Chief of Party.
      Instrumentman.
      Rodman.
      Chainman.
    Hackensack.
      Chief of Party.
      Instrumentman.
      Rodman.
      Chainman.]


  [Chart: Fig. 21.

  Organization After the Tunnels Had Been Holed Through.

                        Resident Engineer.
                 ________________|_______________
                |             |      |           |
            Assistant         |      |      Assistant
            Engineer.         |      |      Engineer.
         _______|______       |      |           |
        |              |      |      |           |
  Cost and Office  Field Inspection. |      Alignment.
      Records.    _____|_____________|
                 |                   |
              Tunnels.    Conduit Inspector.

  Cost and Office Records.
    Two Inspectors.
    Two Clerks.
    Stenographer.
    Telephone Operator.
    Messenger.
    Janitor.

  Tunnels.
    Chief Inspector.
      8 Tunnel Inspectors.
      2 Mixer Inspectors.
      1 Night Inspector.
  Conduit Inspector.
    Inspector, Hackensack Approach.

  Alignment.
    1 Instrumentman.
    1 Draftsman.
    2 Rodmen.
    3 Chainmen.]

The general organization of the staff is shown by the two diagrams,
Figs. 20 and 21. Fig. 20 shows the organization previous to the holing
through of the tunnels, during which time a separate office was
maintained at the western end for the use of the men stationed there;
Fig. 21 shows the organization during the latter part of the time, after
the tunnels were holed through. The Assistant Engineer in charge of the
construction was J. R. Taft, Assoc. M. Am. Soc. C. E.; the Chief
Inspector, J. S. Frazer, Jun. Am. Soc. C. E., had charge of about 75% of
the work of the lining of the tunnels. The alignment has been from the
beginning under the charge of R. L. Reynolds, Assistant Engineer.

       *       *       *       *       *
           *       *       *       *
       *       *       *       *       *

  Errors and Notes:

  Each Plate was printed with the same header:
      PLATE __.
      TRANS. AM. SOC. CIV. ENGRS.
      VOL. LXVIII, No. 1154.
      LAVIS ON
      PENNSYLVANIA R.R. TUNNELS: BERGEN HILL TUNNELS.
  These headers were omitted for the e-text. Captions beginning in
  “K” with a number were printed directly on the photograph; some
  readings are uncertain and are indicated by question marks (?).

  In the tables of Figures 1-4, variation between “to” and “-”, and
  formatting of table entries, is as in the original.

  [Fig. 1, table]
  Per cubic yard, whole tunnel section: 3-33
    _may be error for “3-3.3”_
  [Fig. 1, last line of table]
  Total Pounds
    _text reads “Pound”_
  Figs. 3 and 4, and Plate XXIV
    _apparent error for “Figs. 3 and 4, Plate XXIV” (usual form)_
  [Figure 15 A, B, C...]
    _letters other than “B” do not appear in the printed Figure_
  [Figure 15, caption]
  DETAILS OF “WEASEL”
    _quotation marks look hand-written, but printed text has spaces_
  [Figure 15, “Index” (small table)]
  Multi-Duct Mandrel
    _text reads “Mult-Duct”_
  which would be satisfactory to the engineers
    _text reads “satifactory”_

  Missing or superfluous punctuation was silently corrected.