Q2 Z2,(Q2) Z2(Q2) - Institute for Water Resources - U.S. Army

In the examination of barge tows, it was found that the tow's
output was materially affected by characteristics of the waterway,
namely, width, depth, and stream velocity. The comparable variables
in the case of rail transportation are the gradient and curvature of
the track. The effect of gradient of terrain on train performance
is illustrated in Table 5.3. The train whose output is examined in
that table consists of fifty fully-loaded, 70-ton freight cars pulled
by one 2,000-horsepower locomotive. The table ends with a grade of
3 percent because few grades exceed that amount. 19
Gradient
(percent)
0
.5
1.0
1.5
2.0
2.5
3.0
Table 5.3.
EFFECT OF GRADIENT ON TRAIN PERFORMANCE FOR FIFTY
70-TON BOX CARS PULLED BY 2000-HORSEPOWER LOCOMOTIVE
Speed
miles/hour
28.96
9.31
5.30
3.69
2.82
2.29
1.92'
Output
ton-miles/hour)
101,374
32,600
18,540
12,903
9,885
8,009
6.731
Curvature, the other terrain factor to be considered, also im-
pedes train performance, although not so dramatically is does grad-
ient. The following table illustrates the effect of curvature on
train performance for the same train considered above. Hay reports
that railroad curves for high speed traffic--70 to 100 miles per
hour--are held, to 1 to 2 degrees and 2 to 3 degrees for 'moderate
speeds of 45 to 69 miles per hour. Curvature may go as high as 30
to 40 degrees, but curvature above 20 degrees is not recommended. 20
157'