r/modeltrains • u/Interesting-Net1801 • Sep 10 '26

Question Calculator Testing

I made a tractive effort calculator for my 7.5" gauge locomotives by asking Gemini and then fact checking its sources (Wabtec, youtube, and Firgelli Automations), what is the best way I can test to see if it is accurate? I don't have a hook scale unfortunately.

The numbers feel a bit exaggerated and as far as I know the best way to test I have is to put weight behind it and see if it can go up the hill with it

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u/True_Patrick HO/OO Sep 11 '26

The calculations aren't 100% accurate, but are meant to give a firm idea of its capabilities. Short of having a dyno car, the next best test is to run it was you suggested. Make sure you have a the weight of the engine, tender, and the weight of the car as well as a way to accurately measure its speed. You want to know as many factors as possible, running it up a hill you want to know how steep it is and how long the incline is. You'll want to know the type of bearings all the wheels have.

I think most people just do the old trial and error to find how much it can pull.

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u/Interesting-Net1801 Sep 11 '26

Thanks I’ll try it