Re: Calculating Motive Power Requirements

John Larkin

Remember that prototype tonnage ratings were done by first estimating how many tons a locomotive could pull over the assigned district, then often modifying the rating when experience dictated a change was necessary.  Some steam engines simply steamed and pulled better than anticipated and tonnage ratings would increase.  Thus the idea of just adding cars until the train stalls is essentially what was done on the prototype (yardmasters who needed to get rid of the last two cars on a track, for example)
and should work equally well on models, especially if there are somewhat uniform weights involved.

John Larkin

On Saturday, August 15, 2015 10:25 AM, "'Nelson Moyer' ku0a@... [STMFC]" wrote:

I had another reply failure, so here’s the text of the failed message:
In my case, the ruling grade of 2% is in the helix, so it’s out of sight, over the horizon, over the rainbow, or whatever. I’ve already done pulling power on my locomotives on a straight 2% grade to get an idea of how many NMRA specification weighted cars they can pull. I don’t have the helix built yet, so I can’t repeat the tests on the helix curve.
I have the option of using helpers on the helix, or doubling the hill, which may be necessary when using steam power. There is a helper pocket at the bottom of the helix, and a passing track at the top of the helix.
Nelson Moyer

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