Paul A. Seurot, M. Am. Soc. C. E., acted as Office Engineer in charge of the drawing office, and Mr. J. Soderberg as Mechanical Engineer in charge of the mechanical drafting. Prior to the construction of the above works Mr. C. J. Crowley acted as Resident Engineer on the construction of the Weehawken Shaft, and J. F. Rodenbough, Assoc. M. Am. Soc. C. E., on that of the Manhattan Shaft.
Table 1 shows the quantities of certain materials and other statistics regarding this Division.
TABLE 1.
| Bergen Hill. | River Tunnels. | Term. Sta.-W. | |
| Excavation disposed of (or displaced), in cubic yards | 263,000 | 238,995 | 517,000 |
| Cast metal used in tunnel, including cast iron and cast steel, in tons | 64,265 | ||
| Steel bolts used, in tons | 2,606 | ||
| Cement used (concrete and grout), in barrels | 95,000 | 145,500 | 33,000 |
| Concrete, in cubic yards | 95,000 | 75,400 | 18,500 |
| Dynamite for blasting, in pounds | 600,000 | 100,400 | 206,000 |
| Brickwork, in cubic yards | 4,980 | ||
| Structural steel (including Pier 72), in pounds | 50,000 | 3,141,000 | 1,475,000 |
The number of passengers carried on the Elevated Railroad and surface lines of Ninth Avenue during the underpinning of these structures was about 125,000,000.
The Board of Engineers, organized by the Pennsylvania Railroad Company in January, 1902, immediately took up the matter of route and grade. The center line, which had been assumed as the center line of 32d Street extended westward, was slightly changed.
The grade adopted was approximately 2% descending westward from Ninth Avenue, which would place the tunnel well below the Government dredging plane of 40 ft. below mean low water at the pier head line; thence westward on a lighter grade still descending until the deepest portion of the river was reached where the top of the rail would be about 90 ft. below mean high water, this location giving sufficient cover over the tunnels to insure stability and guard against the possibility of shipwrecks settling on the tunnels. From this point to the portal an ascending grade of 1.30% was adopted, which gave the lines sufficient elevation to cross over the tracks of the New York, Susquehanna and Western and the Erie Railroads, which run along the westerly base of the Palisades. Owing to the exigencies of construction, these grades in the river were very slightly modified. [Plate VII] is a plan and profile of the tunnels as constructed.
Plate VII.— Plan, Profile, and Triangulation, North River Tunnels
The Board of Engineers early in 1902 took up the question of supports for the tunnels under the North River, and various plans and schemes were considered. It was finally decided to support the tracks on screw-piles carried through the lining of the tunnels, as originally proposed by the writer.