MK< HANK AL INSTALLATIONS FOR TUNNEL WoltK Itfl 



is 8,500 ft. long, and was driven through clay by means of a 

 shield, as described in the succeeding chapter on the shield 

 system of tunneling. The mechanical plant installed for pros- 

 ecuting the work was very complete. To furnish steam to the 

 air compressors, pumps, electric-light engines, noisting-engines, 

 etc., a steam-plant was provided on each side of the river, con- 

 sisting of three 70 H. P. and four 80 H. P. Scotch portable 

 boilers. The air-compressor plant at each end consisted of 

 two 20 X 24 in. Ingersoll air compressors. To furnish light to 

 the workings, two 100 candle-power Edison dynamos were in- 

 stalled on the American side, and two Ball dynamos of the same 

 size were installed on the Canadian side. The dynamos on 

 both sides were driven by Annington & Sims engines. These 

 dynamos furnished light to the tunnel workings and to the 

 machine-shops and power-plant at each end. Root blowers of 

 10,000 cu. ft. per minute capacity provided ventilation. The 

 pumping plant consisted of one set of pumps installed for per- 

 manent drainage, and another set installed for drainage during 

 construction, and also to remain in place as apart of the permanent 

 plant. The latter set consisted of two 500 gallon Wnrthington 

 duplex jminjw set first outside of each air lock, closing the ends 

 <>f the river portion of the tunnel, for permanent drainagt, 

 a drainage shaft was sunk on the Canadian side of die river, 

 and connected with a pump at the bottom of the open-out 

 approach. In this shaft were placed a vertical, direct acting, 

 comjKiunil condensing pumping engine with two I'.M in. high- 

 -ure and two 33) in. low-pressure cylinders of 24 in. stroke, 

 connected to double-acting pumps with a capacity of 8000 

 gallons |*-r minute, ami also two duplex pumps of 500 gallons 

 capacity per minute. For permanent drainage on the American 

 side, four \Vnrthington pumps of 8,000 gallons' capacity were 

 installed in a pump-house set back into the slope of the open- 

 cut approach. For the permanent drainage of the tunnel 

 proper two 400 gallon pumps were placed at the lowest point 

 of the tunnel grade. Spoil coming from the tunnel proper was 



