Hi,
I would like to add a coal trestle to my paper mill and I have noticed in MR that alot of folks put quite large grades on the track leading up to the trestle. What is a typical grade for such an approach?
Thanks, Hansel
You are probably going to get several different answers for this.
I would make it as shallow as I could in the space that you have available. But it still would depend some on how many cars the top of the trestle will hold. If it is long and holds three cars, a shallow grade is desired. If it is short and only holds one car at a time, you could go with a steeper grade, just as long as your locomotive can get the car up there.
On something like this I would try to stay away from anything steeper than 4%. At the same time, I would set up a test track on a board. Put a loco and the number of cars that you want to deliver to the trestle on the track and connect power. Tilt the board and see if you can start the train. If you can, fine. Keep increasing the grade until the loco is unable to start the cars. Then you will have some idea of what you can and can’t do.
The transition from table surface to the grade going up, and then from the grade to the level of the trestle will have to be figured into the length of the grade as well.
4% really? I thought I have seen steeper grades but this was only on models. I would only have one 70 ton coal car to push up the grade and with today’s engines it isn’t a problem to push one car up a very steep grade.
Thanks, Hansel
I’ve seen photos of models that are much steeper than 4%, but darned if I know how they do it. Four percent is about all mine can handle before wheel slippage sets it. Lack of power certainly isn’t the problem.
There is an old coal supply track with a historical marker in Barnegat, NJ. The only rails left indicate that it went from normal track grade to a 8’ elevation in about 100’ - isn’t that 8%? - and in 1:1 scale!![8D]
You can make it as steep as one engine can push a car up the grade.
Here is the trick:
The engine and car have to be able to negoiate the vertical curve at the top and bottom of the grade.
That is the real limitation and unfortunately you will have to try that yourself because its a function of how long the transition is, whether you are using diesel or steam, pilot trucks or not, what length cars you are shoveing, what length locomotives, etc. I suggest getting a couple pieces of flex track and mocking up a couble grades to see how it works. Take two pieces of 1x4 a foot long and another longer piece. Tack flex track to the 1x4’s, leaving about 6"-8" between 1x4’s. Then raise the end one foot piec up level (use books or piles of magazines to raise it) and let the middle foot long piece just “float”. The flex track will form natural vertical curves at the top and bottom. Try running an engine and couple cars up and down the grades. Then raise the end 1x4 a half inch or so and try it again.
Dave H.
I wonder if the real world railroads every used reacher cars for this. If the grade is so steep that the engine has a tough time with one or two loaded cars in addition to getting its own mass up that grade an appreciable distance, wouldn’t it make sense to use two or more empty reacher cars, say light flat cars? Place them in front of the engine and hook up to two or more hoppers loaded with coal. Shove the two loaded hoppers up the ramp, but keep the engine on level track where it has the best tractive effort.
I dunno, maybe the additional weight of the reacher cars would amount to the gain in traction on level track. Anyone care to respond?
-Crandell
Selector,
That makes a lot of sense and I’ll bet it would work. I would never have thought of that.
Another not-unlikely possibility for raising one car at a time doesn’t even involve a locomotive. It does involve a steam or electric winch on the end of the trestle and a cable, possibly with a Y-connection at the end to connect to both ends of the hopper’s end beam.
The top of the trestle wouldn’t be quite level, so the empty car would roll as the winch cable unreeled to lower it to ground level. There would be rollers between the rails at the top of the severe grade.
Chuck (modeling Central Japan in September, 1964)
The only reason a real railroad would use idler cars (what you are calling reacher cars) is if the trestle wasn’t able to support the weight of the engine. Since its a paper mill the trestle shouldn’t have to be over about 6-8 feet high, they would more likely dig down if they needed additional clearance.
The really high coal docks were ususally reserved for locomotive coal docks where the coal was gravity unloaded, so it had to be above the hieght of an engine and many of those used a winch to raise the cars up, with the cable attached to the knuckle, not the end sill.
Dave H.
Hansel,
If you don’t want to make an incline and you have some sub platform material like 2 inch foam, you could always try this approch.
I have other pics if you’re interested.
Dave and Chuck, thanks for your responses. I hadn’t considered the winch. But, would what I propose work if we were stuck with a substantial grade and the engine wasn’t up to the task otherwise?
-Crandell
When I was a kid, I watched a CNJ RS-3 shove a hopper car onto a coal dock in Little Silver, N.J. I’m sure the grade was more than 4%, and even though the engine was working hard, it still got the job done .