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.