166 POWER DISTRIBUTION FOR ELECTRIC RAILROADS. 
Power transmission to rotary converter stations is there- 
fore under existing conditions of very limited applicability, 
for purely financial reasons. 
With an available alternating motor for use on the 
cars the matter puts on a very different aspect. Reducing 
transformers would be placed at suitable intervals along 
the line, supplied with energy from high tension feeders 
and feeding the working conductors directly from their sec- 
ondaries. The rotary converters or equivalent machines, 
with the accompanying apparatus, the substation itself and 
all the attendance would be dispensed with. In addition, 
the energy lost in conversion to continuous current—from 
ten to twenty per cent of the whole—would be saved. As- 
suming one hundred kilowatts average output in the sub- 
station, working twenty hours per day, the actual saving 
would amount to not less than half a cent per kilowatt 
hour, $36.50 per kilowatt per year. ‘The abolition of this 
charge for the conversion of energy to continuous current 
would make power distribution from a central station pay 
in a large number of cases where boosters or separate 
generating stations are now the most economical methods 
available. 
Furthermore it would make it possible to employ water 
power far more freely than is at present worth the while, 
and would give a particular impetus to long interurban 
and cross country lines now hampered by the heavy cost of 
transmitting the necessary power. 
Admirable as is this outlook we must not for a moment 
lose sight of the fact that before entering this promised 
land we must have an alternating motor substantially as 
efficient and durable as the present standard railway 
motors. 
It is not, however, necessary that there should be any 
striking similarity in appearance or in methods of opera- 
tion between the two types of motor, or even that the al- 
ternating motor should be suited to all conditions under 
which continuous current motors are now worked. Alter- 
nating and continuous currents have found for themselves 
  
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