ALTERNATING MOTORS FOR RAILWAY WORK. 193 
and long distance work they are not only important as a 
part of the distribution, but have some material points of 
superiority. In such work, with infrequent stops at stated 
intervals, their tendency 1o run at a uniform speed ‘irres- 
pective of grade and load must be very useful in main- 
taining the running schedule. ‘I'he maintenance of speed 
in spite of moderate variations in voltage is also useful in 
working long feeders at variable load, and the possibility 
of working at high voltages greatly simplifies the problem 
of drawing large amounts of energy from the working 
conductors. 
The alternating motor is then fortunately best adapted 
to that class of work in which the exigencies of distribu- 
tion make it most necessary. In high speed and long dis- 
tance work lies its chief strength, and when this kind of 
railroading is attempted in earnest it is quite safe to say 
that alternating motors will be used. 
For light railways running considerable distances 
across country also, the alternating motor is peculiarly 
adapted. 
In no way can the importance of this branch of work 
be exhibited more forcibly than by computing the initial 
and operating expense of a road under assumed condi- 
tions; first, utilizing continuous currents; second, employing 
transmission to substations with rotary transformers, and 
finally, using an alternating distribution with alternating 
motors. It is, of course, quite impossible to select a case 
that will be exactly equally fair to all three methods, but 
we can, perhaps, approximate to a fair general case. 
Let us assume an electric road thirty miles in length 
running through a series of villages with two cities of 
moderate size as termini. For simplicity we will assume 
that the cost of fuel and labor is uniform throughout the 
line so that the location of the station is uninfluenced to 
any extent by local conditions. The train service we will 
assume to be conducted on a twenty minute headway, the 
actual running time being two hours, including stops. 
This would keep twelve cars in service. We will also as-