With practical measurements of voltage and current to the drive motor(s) under stall conditions if possible, or under full acceleration under maximum load, and an assumed motor efficiency. Best bet.
1. Determine the diameter of the cylinders and piston stroke of locomotive engine 2. Determine the wheel diameter of the locomotive 3. Find the mean pressure of the piston for the generator engine 4. Multiply the cylinder diameter by itself 5. Multiply 324 by the stroke length 6. Multiply 7,776 by the mean pressure of the piston 7. Divide 622,080 by the diameter of the locomotive wheel.
I'd start with the fuel flow rate, its heating value, an assumed efficiency of a diesel motor and an assumed efficiency of a generator. The diesel motor burns fuel, drives a generator to produce electrical power which is then used to drive electric motors at the wheels.
