Re: lbf. vs Tractive Effort

Joe Weigman Wrote:
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Not so detailed as I'd prefer; I try to keep it to a few paragraphs rather than write a novella.

You can come at power from the back side of the equation too: If you know your load and know your speed and know the route/curves/grade/weather you can work out the train resistance and calculate horsepower on the basis of work done. This isn't necessarily the locomotive's maximum--that'd depend on the nature of the run in question--but it'll tell you what your train is actually doing. This is a REALLY effective method for identifying BS high-speed claims by the way; if your train crew tells you they ran a train at a speed that'd require half again as much horsepower as their engine is even capable of generating you know it's a fish story. There are a lot of fish stories in railroading.

Without knowing the specifics of RGS 20's design, I'd expect an engine of its size and weight, from the its era, to make something around 350-500 peak horsepower. Within about that range I'll take it relatively uncritically. Outside that range I might wonder, and dramatically outside that range is going to be straight up wrong. Case in point, the 20 needs a lot more than ~34 horsepower just to pull itself--not even a load--up a 4% grade at 7 or 8 miles an hour. Obviously it made much more than that.