CHAP1LER IX. 
FAST AND HEAVY RAILWAY SERVICE. 
Up to the present time a large proportion of all elec- 
tric railway work has belonged strictly to street railway 
service, a few per cent can be classed as interurban, and 
only here and there have there been any serious attempts 
to beat the locomotive on its own ground. The task is a 
serious one not to be undertaken without good cause. Our 
present locomotive is a wonderfully reliable and efficient 
machine, beautifully adapted for its work, and if it is to 
be replaced by the electric motor, there must be good cause 
for the change. 
The economic relation between the motor and the lo- 
comotive has been several times carefully investigated with 
the uniform result of showing, assuming the same condi- 
tions, no very considerable advantage on either side. It 
is in the variations in the conditions, the exigencies of 
traffic of different kinds, that positive economies in favor 
of electricity or of steam must be sought. 
Without taking up the application of electric power to 
universal railway work, there are three classes of service 
for which it is now admittedly highly desirable, irrespect- 
ive of any saving reckoned on the horse-power-hour basis, 
which does not completely tell the story of ultimate profits. 
In general these three classes have this in common, 
that in each of them electric power gives positive advan- 
tage in earning capacity, aside from the saving in operat- 
ing cost which certainly exists in two of them. The 
classes in question are as follows: 
1. Heavy local passenger traffic. 
2. High speed interurban traffic. 
3. Elevated roads, tunnels, and special service. 
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