Re: Steam locomotive horsepower...

First, no need to double the cylinders. It's diameter squared, not doubled. That's your error. Doing the math suggests you're generating about 235 horsepower at 5 MPH for a very brief period if you're at full cutoff, brief because you're soon reigning in power since you want to stop accelerating.

Edit: I calculated that as having 37 inch drivers since that's what they were specified with as built. 36 inch you gave is probably more reflective of their current condition (somewhat worn), which makes a small increase in the calculation to 241.

Edit: Also, keep in mind that in the calculation you're using, the entry for stroke represents full cutoff. If you use less than that, you'd have to figure out the reduced average pressure in the cylinders accordingly (more math!) to get the result.

Given the light trains you pull, I imagine those locomotives accelerate the load quite easily.

As you know, that isn't the maximum for the locomotive, either. Not even close. What's the heating surface of the C-19 in its rebuilt form? I only know the specs for them in as-built form. A quick guess would put these engines at ~373 horsepower at 8 MPH if you were running at full cutoff with valves on the verge of popping, but in reality it may be a bit higher or lower depending on the actual heating surface versus my guess.

More edit: let's keep your 36 inch wheel diameter. At 5 MPH you're running at only about 46.68 RPM and 155.62 feet per minute piston speed.



Edited 2 time(s). Last edit at 12/27/2011 02:47PM by James.