g. Doubleheading trains or using pushers. If you use two of the

locomotives for each train, as in doubleheading, the GTL is 1,196

short tons which you find by adding the GTL for each locomotive. If

you were using steam locomotives, you would use only 90 percent of

the combined GTL because this is the efficiency that steam

locomotives retain when doubleheaded.

2.12. NET TRAINLOAD

The payload or actual weight of freight a train carries is the

net trainload (NTL). It is the difference between the total weight

of the cars under load and the same cars empty, or the gross trailing

load minus the weight of the empty cars. Military planners do not

total the weight of all cars in a train and subtract, but rather

assume that 50 percent of the gross trailing load is payload. Using

the example presented in the preceding paragraph, the GTL for a

single 0660 dieselelectric locomotive is 598 short tons. The net

trainload for that locomotive on that division is 50 percent of 598

short tons or 299.

If each train carries a net trainload of 299 short tons, you

find the total number of payload tons or net division tonnage that

can be moved over a rail division each day by multiplying the NTL by

the number of trains that run over the division each day. The

following paragraph explains how to determine just how many trains

you can safely operate.

2.13. TRAIN DENSITY

The number of trains that can be safely operated over a rail

division in each direction during a 24hour period is the train

density