A typical working gang, as divided among the various operations, is shown below:
| Superintendence. | ||||||
| ½ | Superintendent | @ | $250 | per | month | |
| ½ | Assistant engineer | " | 150 | " | " | |
| 1 | Assistant superintendent | " | 150 | " | " | |
| Surface Transport. | ||||||
| 1 | Foreman | @ | $2.50 | per | day | |
| 1 | Engineer | " | 3.00 | " | " | |
| 1 | Signalman | " | 2.00 | " | " | |
| 16 | Laborers | " | 1.75 | " | " | |
| 3 | Teams | " | 7.50 | " | " | |
| Laying. | ||||||
| 1 | Foreman | @ | $4.00 | per | day | |
| 8 | Laborers | " | 2.00 | " | " | |
| Forms. | ||||||
| 1 | Foreman | @ | $4.50 | per | day | |
| 4 | Carpenters | " | 3.25 | " | " | |
| 5 | Helpers | " | 2.25 | " | " | |
| Tunnel Transport. | ||||||
| ¼ | Foreman | @ | $3.25 | per | day | |
| ¼ | Engineer | " | 3.00 | " | " | |
| ¼ | Signalman | " | 2.00 | " | " | |
| 4 | Laborers | " | 1.75 | " | " | |
| Mixers. | ||||||
| ¼ | Foreman | @ | $3.25 | per | day | |
| 2 | Laborers | " | 1.75 | " | " | |
The superintendent and assistant engineer looked after the brickwork and other work as well as the concrete. The surface transport gang handled all the materials on the surface, including the fetching of the cement from the cement warehouses.
The tunnel transport gang handled all materials in the tunnel, but, when the haul became too long, the gang was reinforced with laborers from the laying gang. Of the laying gang, two generally did the spading, two the spreading and tamping, and the remaining force dumped the concrete. The general cost of this part of the work is shown in [Table 13].
The figures in [Table 13] include the various items built into the concrete and some that are certificate extras in connection with the concrete, such as drains, ironwork and iron materials, rods and bars, expanded metal, doors, frames and fittings, etc.
Water-proofing.—According to the specifications, the water-proofing was to consist of seven layers of pitch and six layers of felt on the side-walls and a ½-in. layer of mastic, composed of coal-tar and Portland cement, to be plastered over the outside of the arches.
By the time the work was in hand, some distrust had arisen as to the efficiency of this mastic coating, and a great deal of study was devoted to the problem of how to apply a felt and pitch water-proofing to the arches. The difficulty was that there was no room between the rock and the arch or between the timber and the arch (as the case might be) in which to work. Several ingenious schemes of putting the felt on in layers, or in small pieces like shingles, were proposed and discussed, and a full-sized model of the tunnel arch was even built on which to try experiments, but it was finally decided to overcome the difficulty by leaving out the arch water-proofing altogether, and simply building in pipes for grouting through under pressure, in case it was found that the arch was wet.
As to the arch built through the length excavated by cut-and-cover on the New York side, it was resolved to water-proof that with felt and pitch exactly as the side-walls were done, the spandrel filling between the arches being raised in a slight ridge along the concrete line between tunnels in order to throw the water over to the sides. The portions of arch not water-proofed were rather wet, and grouting with a 1:1 mixture was done, but only with the effect of stopping large local leaks and distributing a general dampness over the whole surface of the arch.
TABLE 13.—Cost of Concrete in Land Tunnels, in Dollars per Cubic Yard.