As the engine weighs 165 tons and the
caboose 15 tons, 180 tons should be added, making the figures, 1,045 and
1,125 tons. Thus the length of the grade, 2.44 miles, makes the tractive
power on it 92% of that on shorter grades.
On Hill _B_, the rating, adding 180 tons as above, is 1,160 and 1,230
tons, respectively, giving 94% for 3.57 miles.
On Hill _C_, the rating, with 180 tons added, is 1,130 and 1,230 tons,
making 92% for 4.41 miles.
Taking the same basis as the author, namely, 4.7 lb. per ton, rate of
grade x 20, and weight on drivers, gives:
Hill _A_, 18.078%, remainder of division, 19.462%
Hill _B_, 20.068%, " " " 21.279%
Hill _C_, 19.549%, " " " 21.279%
It will be noted that the author uses the weight on the drivers as the
criterion, but the tractive power is not directly as the weight on the
drivers, some engines being over-cylindered, or under-cylindered; in the
class of engines above mentioned the tractive power is 23.35% of the
weight on the drivers.
The writer made a study of several dynamometer tests on Hill _C_. There
is a grade of the same rate, about 1 mile long, near this hill, and a
station near its foot, but there is sufficient level grade between this
station and the foot of the hill to get a good start.
Pages:
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29