fuel consumption of a diesel locamotive.?

Answer 1

Of course there are many different engines. Lets just pick a run of the mill, no frills EMD SD 45.

The "load" is the determining factor, but it is not the "load" being pulled. The load is put on the prime mover (the diesel) according to electrical consumption requirements. Consequently, the tonnage the locomotive is handling increases the load on the prime mover. This load is constant, relative to speed and throttle position. By way of example, if the engine is under full load, at full power, it doesn't matter if it is going 10 MPH or 60 MPH. This does come in to play, however, when determining the "Ton Miles Per Gallon" of fuel consumed. This is the standard most rail companies use to determine fuel efficiency.

With our SD 45 benchmark, full power output, "Run 8", also referred to as full rack, will consume diesel fuel at around 196 gallons per hour, at 916 RPM. At Idle, the engine will consume 6 gallons per hour. If equipped with a high speed idle, which runs the idling engine faster during freezing conditions, consumption runs around 9 gallons per hour.

Newer engines have fewer cylinders, produce more power and with less fuel consumed, on some, as low as 168 gallons per hour.

Answer 2

Are you starting your own railroad?
The consumption is based on the load the locomotive is pulling.
Several gallons a minute under heavy load.
But it is still less per pound of load than a truck or car.