The number of tons of railway supplies needed to operate a
railroad varies with the length of the line and the complexity of the
operation. However, railway supply tonnage is generally rather
large. Experience has shown that railway operating supplies make up
approximately 5 to 15 percent of the tonnage hauled over a railroad.
Such supplies are many and varied, but the three principal kinds are
fuel, lubricants, and spare parts for the motive power and rolling
stock used in the operation. The discussions in this chapter are
confined to these three kinds of supplies and the methods of arriving
at specific requirements of each.
Steam locomotives use either coal or oil to generate their
power, and dieselelectric locomotives use oil to run their diesel
engines. Fuel consumption rates for steam locomotives are based on
the number of pounds and for dieselelectric locomotives on the
number of gallons used. Both are computed by the same method. When
more than one type of locomotive is used on a division of rail line,
the fuel required for each type must be computed separately.
The fuel required for road engines and switch engines is
determined differently. Fuel for road engines is based on the amount
they use per train mile, while that for switch engines is based on
the amount used per hour. When the monthly requirement for road and
switch engines is determined, a reserve factor is added for each type
of fuel used: 10 percent for coal and 5 percent for oil. The next
three paragraphs explain how to figure fuel requirements for the
various kinds of locomotives.