Challenger of Locomotive 139 



with an approximate total weight including 

 radiator, fuel tanks, etc., of 20 to 25 Ib. per 

 h.p. Such being the case, it is obvious 

 that, per horse-power, the balance is heavily 

 in favour of the motor engine as compared 

 with the heavy and costly steam locomotive. 



The general principle of the Diesel- 

 electric vehicle is quite simple. The equip- 

 ment consists of an engine driving a direct 

 current generator which supplies the cur- 

 rent to the traction motors; these are of 

 standard type. 



It might be asked, " Why Diesel engines, 

 when the internal combustion motor has 

 been brought to such a high pitch of 

 efficiency, also when the cheapening of 

 petrol has so considerably reduced the cost 

 of running such engines, that there is little 

 to urge against their employment? ' It may 

 be pointed out that as on ships the Diesel 

 engine using crude oil results in great 

 economy, so for railway work the cost is 

 much lower than in the employment of 

 petrol, while the efficiency is quite up to the 

 standard of the engine using the latter fuel. 



