At a train show, I recently purchased an ALCO Locomotive Horsepower Calculator. It looked so neat and plus, it was only $1.00. I am wondering if anyone can provide me with information on how these were used. Were they used for training or is this something engineers kept in the cab at all times? Thanks. Tyler.
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Locomotive Engineers wouldn't have been using that. Those types of calculators would have been used by the Mechanical Department shop forces generally during load testing. EMD had a similar calculator, and I assume GE would have also.
You would think there were similar calculators that related tonnage/number of cars/percent grade, to horsepower requirement/tractive effort/number of units.
IMO, I could be wrong and often.
Somewhere in the system that puts trains together, someone would have to check the: Can we do this?? Engineer/Conductor/Yard personel?????
There looks to be a magic number range based on the generator readings, volts/amps/watts, so then horsepower. Would anything outside this range be considered off-spec but maybe acceptable to the guys doing shop testing?
As in, " Is this locomotive good enough to send back out again, or should we rip it apart?"
As a fussy old machine shop inspector I used to know said, "Acceptable....not desirable, but acceptable."
I guess the GE calculator would be similar, as Alco used GE electrical components. Opinions anyone?
To my knowledge, GE never had a "horsepower calculator". One reason is that generator efficiency varies with generator speed (rpm) and excitation level. Even if the generator efficiency was constant, to determine the HP of the diesel engine (net input into the generator for traction), you would have to make corrections to the fuel heat value, altitude, and temperature to determine true engine "input for traction under standard conditions". Of course this is not the final answer, as the traction motors are not 100% efficient either, and their efficiency changes with speed, and of course you should deduct the HP required to move the locomotives if you want "drawbar HP".....
GE did have a "trailing tonnage calculator, a hard yellow plastic slider type mechanism that had a set of numbers that told the user how many trailing tons could be hauled up a "X%" grade. There were two sets of numbers, one set assumed 40 foot boxcars and a second for "TOFC" (trailers on flat cars). This was from the U25 era. I have one around here somewhere.....
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