FAST AND HEAVY RAILWAY SERVICE. 231 
trical energy to be delivered to our unit train to maintain 
a uniform speed of thirty miles per hour is about eighty 
to eighty-five kilowatts per train on a level track. To 
maintain a thirty mile per hour schedule under ordinary 
conditions, including stops and the net effect of such casual 
grades as might generally be met in suburban work, might 
require 100 k. w., but the mean daily output per train in 
service would hardly rise above the original figure of eighty 
to eighty-five kilowatts. 
During crowded hours an extra trailer would often 
have to be carried. This would add about twenty-five tons 
Amperes 
  
Street Ry.Journal 
KIG: | TIS. 
to the weight of the trains and would call for about thirty- 
six additional horse power, bringing the total kilowatts for 
the train up to nearly 120. 
This estimate of power, based on known data as to the 
weights and speed, is fully borne out by experiments on 
trains in actual operation. 
Figs. 118 and 119, give the actual power taken to drive 
trains of five and four cars over a substantially level track 
at approximately thirty miles per hour. No continuous 
records of speed were taken, but the averages were about 
as stated, sufficiently near for a fair comparison. Fig. 1181is 
the record of a run with a train consisting of a motor car 
and four trailers weighing, with a moderate load of pas- 
sengers, very nearly 122.5 tons, a trifle more than double 
the weight of our assumed standard train. The average