horse-drawn rail car
 

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.

A typical Percheron or Clydesdale can pull 4k kilograms. A Belgium can pull 3k kilos and a large Morgan or Courser (Amish cart horse) can pull 2k with only average effort.

The largest single driver controlled rig I have ever seen was a 12 bottom plow pulled by 16 horses.

Wheeled vehicles can cut their weight by a factor of 10... which is why you can push a passenger car weighing 3k pounds by yourself.

The general rules of thumb I've run across for hauling by horses for actual work and not tractor-pull style demonstrations:

1/10 of body weight in dead weight (like a plow or log)
1.5x body weight on wheels on road
5x body weight on rails

So a 75 ton loaded rail car will need at least 15 tons of horse to pull. Figure around 10 draft horses or so.

That's also assuming level track and a relatively low speed (circa 8km/h or 5mph). Hills will need a "booster" team to help haul, and teams will probably need to be swapped every 3-4 hours (let's say 4 just to make it equal to a travel period).

Generally a draisine horse-drawn vehicle was very lightweight, you'd probably need a specialist car. This is good as you can make one up yourself. It would have two axles and probably a canvas bows cover taken from trucks. You'd simply pull more of them if you needed more capacity.

If you need a standard car you can use an alcohol engine dragging one car. Remember it needs a big pneumatic system to slow the car

An interesting idea and I wonder why we don’t see more use of rail lines like this. I seem to recall Stirling mentioned using horse or ox drawn wagons on rails in the first 2 or 3 of his Emberverse series, before it went too fantasy for my liking. I think he even mentioned sped/capacity at some point. Oxen would pull more for longer I think, but would be rarer.

The weight sounds about right for the carriage; it varies depending on what the carriage is fitted for, whether it has its own motors, toilet etc, but 50t is a good average. If the carriage is pretty much being used as a one-time ambulance, then leave it as is. If however it is a conversion that was/is/will be used regularly, then you can shave some of the weight from the 50t. A half decent engineering team might be assigned the role of moding some carriages to serve in the new conditions.
There are a lot of things that are unnecessary in this environment. Based on a little knowledge of UK rolling stock I would suggest it be stripped to bare bones; remember this is Warpac and comfort was never likely to be a major concern anyway, let alone now. Ditch anything that is unnecessary.
Much of the function of train systems relies on connection to the power car and there is little independence in each carriage. There are a lot of pipes and cables that run the length of a train that won’t be needed anymore.
Remove most/all seats. Lightweight rig to hold litters, and any seats left don't need to be heavy enough to withstand the stress of high speed or crashes. Bolt in the lightest ones salvaged from a ruined factory mess room.
Remove the toilet possibly, CET tank definitely! A CET tank is Controlled Emissions Tank and holds whatever goes into the toilet until it can be emptied at depot. It is often to be found slung under a carriage, on the underframe. I doubt anyone will be worrying about effluent going on the tracks when weight can be saved or when horses and oxen are adding their own anyway (side image, locals rushing out when a horse drawn carriage or two goes by to collect the fertilizer!).
Remove anything to do with lighting, heating, p.a. systems. All rely on the power car to work. Lots of pipework and cable runs through a carriage for these. Generators and transformers are slung under the carriage and could be ditched too unless you can power them (generally they are either linked to the power car or use a dynamo system off the bogie axles, but I doubt they’d work at horse drawn speeds). Standby batteries underneath are heavy and useless unless they can be charged.
Much of the underframe equipment for brakes could be ditched; large air tanks, pipework (probably metal), heavy duty callipers and brake shoes. Remember these are designed for stopping not just the 1 carriage but to aid stopping the whole train weighing several hundred tons running at speed. Again, they need control and power from the engine or power car. Carriages have a default, if connections fail then the emergency brakes come on automatically. That would need to be overruled or the horses will be trying to shift the carriage with brakes locked on. Replace with something simpler, such as a simple pneumatic system to cope with any inclines.
Couplings between carriages can go as you're probably running each carriage singularly.
Any weight saving makes the horses job easier and allows you more wriggle room when you work out your speeds. Unless you have a rolling stock engineer in your group, no one’s going to quibble if you say that's a 3t or a 10t saving.

Thanks for the answers
 

The good news is that the PCs aren't likely to use this, so I don't need to worry about them looking too closely.

Stripping out the air-conditioning and heaters, I hadn't thought of that, that's a good bit of weight savings. The air brake equipment can go, I was going to leave in the handbrakes, so the car can be held in place and stopped when needed.

I am thinking this is not a one-time trip, so sleeping arrangements will likely stay. It's not expected to be a high-speed service, just stable and not tie up other transport assets. I am assuming pretty level track, but I know that's never truly level.

10-15 horses sounds like a lot, maybe not saving much in the way of power vs a handful of wagons, and would be more likely to draw a bigger escort than I need for game purposes. Maybe I will drop back to a single alcohol-fueled truck-- rigged for rail-running-- towing the car.
* If I do that, I can leave an axle-driven generator and batteries for lighting.
* If I do that, maybe there's actually an operating room at one end of the car? Nah, that will be a different car, hauled into place nearer the front and left there, while this car is used to shuttle back to a base area.

Plan B would be to take one or more actual ambulances, cut off the cabs and engines, reset the wheels for rail travel, and tow a string of 2-3 of those behind a few horses.

I don't doubt for a second that you could roll such a car with a team of 8 Clydesdales. The Budweiser team routinely pulls 50 tons of rolling weight at a trot without injury. A single Amish Courser will pull a wagon and up to 6 human passengers at a trot without injury (an estimated weight of 2 metric tons with passengers).
Oxen would be the better choice as they do better in rough terrain (do to having a cloven hoof) and can easily drag 3 times their own weight. An ox team of 4 can pull what 8 Clydesdales can pull. Thus, an 8 ox team could easily pull 100 tons of rolling weight. The ox do move slower than horses, however. You will get about 80% of the range of a horse team.

Another thing to keep in mind is the return trip. The Soviets aren't too likely to devote that level of resources to an asset that will only be used half the time. (Doctrinally, Soviet wounded would be evacuated on empty ammunition trucks returning from the front). So to the extent that it didn't impair the primary mission adding features so it could be used for troop transport or cargo carriage on the return trip would be a useful bonus!

An enclosed Amish buggy is about half a ton (a buckboard is under 450 pounds), so either those passengers average 500+ pounds each or the weight estimate seems a bit high; the total weight might be under a tonne if there are children or small adults among the six passengers. Charleston, SC has horse-drawn carriages that weigh 1800 pounds empty and carry 16 passengers while staying under 5000 pounds (2.27 tonnes) total draw weight.

Somewhat contradicting my earlier position, Robert Stevenson was of the opinion that a single horse on well-constructed rail on the level could draw ten tons, but that was during a time when the longevity of the horse was not a concern and they'd be worn out within a couple of years. I suspect the rules of thumb I learned were intended to keep the horses' health as a prime concern and load them more lightly than their maximum for that reason.

Don't forget there's actually a fair bit of infrastructure to support horses, especially that many horses working as hard as these will be. If this is in Poland and it's on The Great European Plain the gradients will be mild but getting further south means steeper gradients and more horses. You will probably have to add a cargo flat to haul fodder. Also remember that for working horses fresh and clean water is a must so the Soviets will have scout out checking the water courses and these can be both a tripwire for the defenders if you want or a lead to the vehicle itself. If you are going through an area where the water is polluted then a water bowser gets added.

If the route is a regular one, perhaps the main exfil route for casualties as well as infil for supplies and new troops, maybe you could add the equivalent of stage stations enroute? This could be a requisitioned farmyard alongside the tracks where the ambulance wagons stop for the night. Place it at the end of whatever distance you decide your wagons can cover in a day, or just before/after harder terrain where the horses have had to cope with any inclines. Horses or oxen could be swapped out for fresh teams, food given to patients and crew, wounds checked etc. It might be manned by a half dozen rear area staff or just a few locals. It may serve as the nearest thing to a military outpost in the area, or it may also be a comms hub, with either telegraph cables, phone lines or the Soviet equivalent of the Pony Express passing through. Either the players can take this over and catch the wagon(s) as they arrive or they have to hit the wagon midway between two stations to avoid the guards from each responding.

Actually, I'm tweaking an encounter that I think someone posted on this forum(?)-- it's a Soviet ambulance wagon train originally, a marauder band has ambushed it, and the PCs have the decision to intervene somehow. Somehow, I got the idea of putting it on rails.

Horse-changing stations are a good idea, I guess I should set some of those up for the PCs to find, too.

There are also Russian medical trains that could be split apart for use. From examining the photos, it looks like their cars are 55-56 tonnes, since TAPA is Russian for tare. The current ones date to 2010, but there's no reason something similar couldn't be introduced earlier.

Possibly not what was asked for, but...

"In Imran’s new Pakistan 90 yr old horse train are still running".
https://www.youtube.com/watch?v=2qJhbRrQbY4

B&W film of the last line in The U.K.:
https://www.youtube.com/watch?v=RfO9ySKK3Ns

Both seem the sort of vehicles that could be built. The second one could even still exist as a Heritage Line somewhere still run by volunteers in T2K...

"The island of Spiekeroog, in Eastern Friesland in Northern Germany".
https://www.urban-transport-magazine...of-spiekeroog/

Photo of horse drawn rail wagon:
https://parlington.co.uk/structures....cess=struct5_4

Various WW1 photos but two on rails:
https://www.nam.ac.uk/explore/horse-...irst-world-war

No horses but "Cambodia made trains out of bamboo":
https://yesterday.uktv.co.uk/blogs/a...-about-trains/

Wherever there are any changes in gradient that would otherwise prevent the trains continuing under horse/oxen power, install a station with cables. Build a winding house adjacent to the tracks, and run the winch off of either steam or alcohol power. The carriages can be hauled up or lowered by winch and the livestock moved either by trail alongside or even given a ride on special wagons.

I think this canal has a similar idea: "The inclined planes".
https://en.wikipedia.org/wiki/Elbl%C4%85g_Canal

Boats on railway lines... and powered via water wheels!

Featured, in The UK, on last night's 'The Architecture The Railways Built'.
https://uktvplay.uktv.co.uk/shows/th.../6278051944001

https://en.wikipedia.org/wiki/The_Ar...Railways_Built

Interestingly, I found today that the part of Sweden that I'm setting my one-shot adventure, has a high-speed rail line, regraded and opened in 1997! So lots of smooth curves and double track (and/or very long passing sidings).

Sounds more likely for a horse-drawn line?

May want to dig more and see if coaches are even light-weight than I thought earlier?

Back in the late 90's I worked at a rolling stock maintenance depot. We were just designing new EMU's (Electric Multiple Units). The older slam door stock, such as the Class 411, were 30-40 years old and were to be replaced by the then new 375's. The old stock was in the 160 ton range for a 4 car unit. The weight saving per 4 car unit was around 25-30 ton, which is quite a consideration without also stripping out anything unnecessary. I also remember that some of the equipment, primarily the traction motors I think, were based on Swedish designs and they had a test train in Sweden with an old 411 carriage and new traction motors and brakes to use as a test vehicle. It ran on a short track and our engineers were impressed that it was got up to speed and safely stopped in such a short distance, even on icy rails.

This is the idea I was thinking of for coping with inclines
https://en.wikipedia.org/wiki/Cable_railway
I avoided suggesting a funnicular style as that is generally 1 carriage going down as 1 comes up, which presumes a regular passing of carriages in your world to make it work.