196 POWER DISTRIBUTION FOR ELECTRIC RAILROADS. 
would be as above, about I.5 cents for 2,000,000 k. w. h. 
per year. 
Now coming to the transmission systems proper, with 
a substation and rotary transformers the cost of the funda- 
mental station, with double-ended generators would be 
about the same as for an ordinary continuous station. For 
the transmission there must be added a set of raising trans- 
formers of about 300 k. w. costing, say, $10 per kilowatt, 
and extra switchboards and subsidiary apparatus amounting 
to, say, $1000. The line will have the advantage of high 
voltage, but the drop will have to be small since the loss in 
transformers and the rotary transformer must come out of 
the fifteen per cent allowed as total. With the best efficien- 
cies that can be expected from these the line loss mnust 
not exceed four per cent. The voltage of transmission 
may be taken as 10,000, hence the drop would be 400 volts. 
The copper must, of course, be figured as a complete metallic 
circuit, and the formula will become 
  
SO, 
V 
in this case the current may be taken as thirty-five to make 
allowance for residual lag and L., is about sixty-eight. 
We get, therefore, for the transmission line 
W= 44X3X35X 1156><4:53,4081bs_’ 
400 
in all costing, at 15 cents per pound, $8o12. At the sub- 
station there will be switchboards, transformers and 
rotary transformers for 300 k. w., which with the house 
may be lumped at $10,000. 
Beyond these costs of transmission is the distribution 
system of feeders, which will cost the same as in Case I, 
together with the maintenance and depreciation of the 
transmission plant and labor at the substation, in all, say, 
$4000 per year. And even after this comes the fact that 
although the voltage on the working lines can be held 
within the fifteen per cent limit of loss, we still have the 
energy loss in the distribution system of feeders. 
With alternating motors the case is very different.