232 POWER DISTRIBUTION FOR ELECTRIC RAILROADS. 
voltage was 530 and the average amperes are very nearly 
290, or 154 k. w. Since the air resistance for four cars 
is but a trifle more than for two, the close agreement 
of this run with our estimate is obvious. 
Fig. 119 shows a run with one motor car and two trailers 
weighing with the passengers 89.5 tons; speed about the 
same as in Fig. 118 and average voltage 475. ‘The average 
current appears to be about 230 amperes, giving 109 k. w. 
total output, which again, reduced to a two-car, sixty-ton 
basis gives in the vicinity of eighty kilowatts for the nor- 
mal train. Another run over the same track as in Fig. 119 
Amperes 
&9 
S S 
g 
  
S 
Street Ry,Journal 
FIG: 110, 
with a three-car train two tons lighter, and in the opposite 
direction showed an average power consumption of 125k 
w. The same motor car was used in all three tests. The 
sudden increases in the current were mainly due to sudden 
changes at the controlling apparatus causing rapid accelera- 
tion. These very large momentary currents are, of course, 
undesirable and can be much reduced by careful handling 
and better adjustment of the controller to its work. 
The normal average current for such a train at 500 
volts would then be not far from 160 amperes. Witha 
working voltage of about 600 at the motors, which is a 
desirable arrangement, about 133 amperes would be re- 
quired. One would not go far wrong, then, in taking for 
ordinary cases 200 amperes as about the largest average 
which would be called for by any one train, allowing the 
use of two trailers when convenient. The ordinary loaded