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.