horse-drawn rail car

[Adm.Lee]

I suspect an answer lies somewhere in this forum, but I'm not finding it easily.

Assume a standard pre-war railroad car, preferably a passenger coach or sleeper. I am presuming horses could be hitched to one, to pull it along. Any estimates on how many would be needed? Two, four?

I'm thinking about an encounter with a Soviet ambulance train, using a coach (or two?) to carry wounded from a front-line area to a rear-area hospital. Rail travel might be more smooth & comfortable than an unsprung wagon on a potholed road. We're not looking for speed, but smoothness.

I found that a European-style coach might weigh 50 tons, 75 fully loaded.

Isn't there something said about rail wheels being 7x more frictionless than road wheels?

Worst case, I'm going to say 4 horses, and my players probably won't call me on it.