106 POWER DISTRIBUTION FOR ELECTRIC RAILROADS. 
nected that in case of accident to one the others can carry 
on its load with a fair degree of efficiency. This mutual 
relation is important in that it permits a smaller reserve 
capacity than would be necessary were the stations inde- 
pendent. For example, the present plant in the Charlestown 
station consists of two 800 k. w. generators each coupled 
direct to a compound condensing Corliss engine. It is an 
ideal plant for the purpose, but as a separate station it 
would have too few units for safety unless one of the pair 
should be virtually held as a partial reserve. It is never 
safe to have an independent station contain so few power 
units that the crippling of one can interfere seriously with 
the operation of the system. 
The second class is composed in the main of inter- 
urban roads too long to be conveniently supplied from a 
single station. In such cases the use of two or more power 
stations is the simplest way out of the difficulty, and these 
stations, having similar functions, are naturally of similar 
size and character, and so distributed as to supply similar 
lengths of track as far as practicable. As long interurban 
roads are only just developing, instances of these distributed 
stations are not yet at all numerous. ‘The interurban sys- 
tem centering in Cleveland, O., furnishes the best example 
of such practice. This is shown in a sketch map in Fig. 62. 
It consists substantially of three roads, the Akron, Bedford 
& Cleveland, the Cleveland & Elyria, and the Cleveland, 
Painesville & Eastern. ‘The first mentioned is about thirty 
miles long with two power stations, A and B, of the figure. 
The former furnishes current for six miles north and nine 
miles south, the latter nine miles north and five and a half 
miles south. The two stations are each of 500 k. w. capacity 
and are substantially duplicates. The second road is sev- 
enteen miles long and has also two power stations, C and 
D. Here C, of about the same size as A and B, sends cur- 
rents in both directions while D, considerably smaller, 
handles the section of line nearest the Elyria terminus. 
The third road is not quite completed, but will be about 
thirty miles long. It is now supplied with power from the