CEMP-E
TI 850-02
AFMAN 32-1125(I)
1 MARCH 2000
Table 3-6. Design Gross Car Weights
Nominal Car Capacity
70
80
90
100
120
140
(tons)
Design Gross Weight
105
115
125
135
160
190
(tons)
Note: 140-ton cars (nominal capacity) are representative of those carrying 2 M1 Tanks.
(2) For field check, car capacity is normally stenciled on the side of each car in pounds, labeled
CAPY. For example, the marking on a 70-ton car would appear as: CAPY 140000.
6. TRIAL RULING GRADE.
a. A trial percentage for the ruling grade can be determined for guiding the first stages of route
selection, using equation 3-3. (The 0.15 constant in the equation indicates that the average rolling
resistance for each car is equivalent to pulling the car up an additional 0.15-percent grade).
G=
- 0.15
TE
20(WEng + Ncars x Wg )
Eq 3-3
G
=
Effective ruling gradient (percent), where the grade length is equal or greater than train
length.
TE
=
Usable locomotive tractive effort (pounds).
=
Weight of Engine(s) (tons).
WEng
NCars
=
Number of cars in train.
Wg
=
Average gross weight of a car (tons).
b. All curvature within the limits of the ruling grade should be grade compensated, as described in
paragraph 4 of chapter 3.
c. A ruling grade that is steeper, but shorter, than the calculated ruling grade can also be used as long
as the total train resistance of the cars on the grade and the cars off the grade does not exceed usable
locomotive tractive force.
3-6
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