Lubrication.—In the lubricating system three distinct systems were used, each requiring its own special grade of oil.
The journals and bearings were lubricated with ordinary engine oil by a gravity system; the oil after use passed through a "White Star" filter, and was pumped into a tank about 15 ft. above the engine-room floor.
The low-pressure air cylinders were lubricated with "High Test" oil, having a flash point of 600° Fahr. The oil was forced from a receiving tank into an elevated tank by high-pressure air. When the tank was full the high-pressure air was turned off and the low-pressure air was turned on, in this way the air pressure in the oil tank equalled that in the air cylinder being lubricated, thus allowing a perfect gravity system to exist.
The steam cylinders and the high-pressure air cylinders were fed with oil from hand-fed automatic lubricators made by the Detroit Lubrication Company, Detroit, Mich.
"Steam Cylinder" oil was used for the steam cylinders and "High Test" oil (the same as used for the low-pressure air cylinders) for the high-pressure air cylinders. The air cylinder and steam cylinder lubricators were of the same kind, except that no condensers were necessary. The steam cylinder and engine oil was caught on drip pans, and, after being filtered, was used again as engine oil in the bearings. The oil from the air cylinders was not saved, nor was that from the steam cylinders caught at the separator.
Cost of Operating the Power-House Plants.—In order to give an idea of the general cost of running these plants, [Tables 3] and [4] are given as typical of the force employed and the general supplies needed for a 24-hour run of one plant. [Table 3] gives a typical run during the period of driving the shields, and [Table 4] is typical of the period of concrete construction. In the latter case the tunnels were under normal air pressure. Before the junction of the shields, both plants were running continuously; after the junction, but while the tunnels were still under compressed air, only one power-house plant was operated.
TABLE 3.—Cost of Operating One Power-House for 24 Hours During Excavation and Metal Lining.
| No. | Labor. | Rate per day. | Amount. |
|---|---|---|---|
| 6 | Engineers | $3.00 | $18.00 |
| 6 | Firemen | 2.50 | 15.00 |
| 2 | Oilers | 2.00 | 4.00 |
| 2 | Laborers | 2.00 | 4.00 |
| 4 | Pumpmen | 2.75 | 11.00 |
| 2 | Electricians | 3.50 | 7.00 |
| 1 | Helper | 3.00 | 3.00 |
| Total per day | $62.00 | ||
| Total for 30 days | $1,860.00 | ||
| Supplies. | |||
| Coal (14 tons per day) | $3.25 | $45.50 | |
| Water | 7.00 | 7.00 | |
| Oil (4 gal. per day) | 0.50 | 2.00 | |
| Waste (4 lb. per day) | 0.07 | 0.28 | |
| Other supplies | 1.00 | 1.00 | |
| Total per day | $55.78 | ||
| Total for 30 days | $1,673.00 | ||
| Total cost of labor and supplies for 30 days | $3,533.00 | ||
Stone-Crusher Plant.—A short description of the stone-crusher plant will be given, as it played an important part in the economy of the concrete work. In order to provide crushed stone for the concrete, the contractor bought (from the contractor who built the Bergen Hill Tunnels) the pile of trap rock excavated from these tunnels, which had been dumped on the piece of waste ground to the north of Baldwin Avenue, Weehawken, N. J.