AMERICAN STEAM ENGINEERING 283 



main engines. Wrought iron pipes up to 5 inches in diameter 

 have cast iron screwed flanges; from 5 inches diameter up- 

 wards, the flanges are welded on. 



The engines were constructed by the Allis-Chalmers 

 company, of Milwaukee, and are eight in numljer. In de- 

 sign they are a radical departure from anything hitherto used 

 m railway power plants. They are four cylinder combined 

 horizontal and vertical engines, consisting practically of a 

 horizontal cross compound engine and a vertical cross com- 

 pound engine, both working upon the same crank shaft, 

 except that the two vertical cylinders are both low pressure 

 cylinders and the other two both high pressure. The cylin- 

 ders measure 44 and 44 and 88 and 88 inches in diameter by 

 60 inches stroke. The speed is 75 revolutions per minute. 

 The cranks, of which there are two, are set at 135 degrees 

 with each other. The power developed under normal con- 

 ditions of running is 8,000 indicated horsepower per engine. 

 The exhaust steam is dealt with by jet condensers, driven by 

 electrical motors. 



The Westinghouse Machine company has recently built 

 and erected some engines at Willesden for the Metropohtan 

 Electric Supply company, which should be briefly noticed. 

 At these works there are four direct coupled units, both en- 

 gines and dynamos being of Westinghouse manufacture. 



The engines are 2,500 horsepower, vertical cross com- 

 pound marine type, with the alternator and exciter arma- 

 ture at the low pressure end of the crank shaft, and a heavy 

 fly wheel governor at the other end. The cylinders measure 

 35 inches and 55 inches in diameter by 36 inches stroke. 

 The crank shaft is 14 inches in diameter. The engine runs 

 at 116 revolutions per minute. The exhaust steam passes 

 into a Wheeler surface condenser, the circulating water 

 being cooled in three Barnard water cooling towers. 



American engine builders as a rule use larger shafts and 

 main bearings than is usual on the eastern side of the ocean. 

 This is due to the fact that Americans have reahzed the neces- 

 sity of fly wheel effect, and that the engine and d)Tiamo are 

 built so as to be able to run 25 per cent overload continuously, 

 and 50 and 75 per cent overload for short periods without 



