Does anyone know the rated tonnage for a Plymouth 12 Ton DDT with a 150HP 4-71 up a 5% grade? The grade is actually 4.7 if it makes a difference.

I would not worry much about going up as I would coming down, particularly if there is no train air brake.
Mike Tillger

I would concur with the brake situation. If this is the original prime mover with factory drive train, I would surmise about 20 to 25 tons. (About one empty standard gauge 40 foot car)

Two foot gauge.

How much are you moving and how far? I agree with the previous posters, one empty car would be the typical normal limit. However, you may already know that you can get more than one car moving up that hill...Stopping is one problem, traction is another.....then you want to keep the load from rolling back down on you or from shoving or sliding you back down the hill.
Trying to move one or two cars to a spot a couple hundred feet away is doable, with relatively little risk. Trying to go a half mile or more up a 5% grade with a similar load is a bit of a different problem.....
Then theres the issue of comming down hill...
Usually,an empty car will brake much better than a loaded one-provided the brakes work and are in good shape. Same goes for hand brakes,except that handbrakes are always less effective than the air brakes....

I would suggest that you keep the load on the uphill side of the loco. On a grade like that, a separated coupling could cause a serious problem before you have the time to react to get the car(s) stopped.

JR

Having switched Heavyweight passenger cars with a 25 ton Plymouth with only straight air on a slight grade, I can attest to stopping being harder then starting, after a couple of "interesting events" we ran some air hoses and hung a single car tester in the cab of the locomotive, this allowed us to use the car air brakes if the locomotive became overwhelmed.

I won't mention what happened the time it was tried with a Trackmobile ;-)

-Hudson

Since we are a closed loop (Rock River Thresheree), we are only going up that grade, with about 80 passengers, one covered car and one open car. Don't have exact weights, but we are making the same grade with a 10 ton Henschel steam locomotive.

I know a 10-ton Plymouth of late 50's vintage, four-wheeled with GM 471 and Allison torque converter, will pull the same train as a 10-ton Henschel 0-4-0, on grades approximating that. It has been doing so for a decade or so. Send me a PM if you want.