OK, so I'm actually starting build something. Not a layout per se, but a big diorama; I'm experimenting with stuff. And of course, since any good layout has to have elevation changes, I've got some grades.
So my question is this: what is the steepest grade that a guy could get away with on a layout? (HO in this case.)
Please note that I'm not really interested in either 1) whether a model loco could actually climb that grade or 2) prototypical grades. If you feel compelled to discuss those aspects, fine; I'm just not asking about them.
What I'm after is the steepest grade that you can build on a layout that will still *look* protypical, that won't look impossibly out of place. One of the grades on my diorama is like this; I think it's something like 25%, and it looks ridiculous. (I'm going to finish the damn thing anyway, just for the exercise.)
The problem I'm running into is that in a small space (3'x7' in this case), you don't really have enough room to, say, run a train from the flats in town way up into the mountains in the background.
Build a couple of switchbacks. I'm assuming you won't actually run anything, but just for the record, you can use 6% to 10% on those switchbacks, and a Shay will walk up them quite nicely. And even haul a car or two. Or three. Just watch for the vertical curves, if you actually run anything. They will have to be at least twice as long as your longest rolling stock.
Bonus! They're prototypical (eg, logging roads, railroads in Peru, etc.) So they will look right. :-)
I just caught part of a documentary today that showed the steepest grade of any working train (without the use of a ratchet system.) Built by the British in some Asian country I believe. I don't recall the details - maybe someone else knows what train I'm talking about.
The disturbing part was the operation. Two guys ride up front to throw sand on the rails to provide traction. It has, if I recall correctly, six switchback points that require the train to climb up the grade in reverse.
One idea is to get a copy of the August 1972 NMRA Bulletin. There was a nice long article on the Skagit River Railway used in the constructon of some dams in the north Cascade mountains. They used an elevator, sorta like a vertical transfer table, to ascend the mountains...ummm...vertically :) It probably wasn't the first, and it's a pretty cool system.
I think that the secret is to remember how we observe grades in real life. Drive along a hilly highway. You can see the grades in the distance, looking almost like a vertical wall...but when you are right on them, which is closer to our normal model railroad viewing distance, you hardly notice they are there, unless you think about it, unless the highway is on a high fill or bridge...if the highway grade follows the surrounding land, it hides the steepness a bit. You can do the same on your railroad -- if your grades are too obvious, build up the ground around them and they won't be.
25% seems a bit high. On some coal trestles or weird industrial sidings it might not be a problem...short, very steep grades are sometimes found on these. I think, ignoring operation problems, that a grade of roughly 8 to 10% is the steepest you can go without your hill starting to look like Lionel Ramp No. 246 - but you might be able to get away with even more if you disguised it with scenery, who knows? (of course, getting a train up grades like that is going to be fun).
There are indeed ways to bring an HO train up grade in 3' x 7'. There are the switchbacks mentioned (remember, these take more space than you might think, since they need a tail track at least one engine and one car long, and the more room the better, since you are going to have to shuffle cars from the down-leading track to the up-leading track whenever you've got a train too long for the switchback tail). If your equipment is small (four-driver steam, SW diesels, Fs and small road switchers, 40' cars) you can lay 15" radius curves and loop the track over on itself. Sure, they're sharp, but I've tested equipment down to 12" and I assure you that there is stuff that will work without problems on 15" R...just not everything. Such overlapping loops need not look unrealistic. Again, it's all in the scenery.
I suggest playing with the plan a bit. Top your railroad with OSB or MDF or some other cheap stuff, get some Atlas up-and-down piers and a bunch of sectional track, and mock up different arrangements, not nailing anything down, and operate them a while until you've hammered out a track plan.
Cordially yours: Gerard P. President, a box of track and some plans
In purely model train terms 1:25 looks ok, but even with good locomotives the length of your train is going to be severely restricted.
1:30 is a lot better and 1:50 will allow you to run longish trains.
15" radius curves will add additional load to your trains, probably (on the flat) as much as a 1:30 gradient, so the combination of sharp curve and gradient will really limit your train length.
In that area you will have to design and build very carefully to get one track over another. Think in terms of the two tracks separating in opposite vertical directions so that each needs to be only half the required length. The gradients will need a vertical transition curve back to level or your trains will uncouple. The most basic way to achieve this would be to have a set-track length of track at half the gradient, or if your track base is plywood then you can use it's flexibility to create the transition from level to gradient.
I've built (long ago) a multilevel layout in a space 1m x 2m (3'3" x
6'7") with lower storage, ground and mountain terminus which was successful but a little toy-like. Maximum train length was about 1150mm (3'10") and the layout could operate 4 trains. (two running at any one time)
I have been told that a 4% grade is about tops for proto. But at the last NMRA in St. Louis, depending on the size of the layout, it was all the way up to 10%. And to get up to a mountain, one guy created a helix that would round and round and round and round (8 times around) at the 4% grade. Then it ran across a tressle bridge to another mountain top and then down and around and around (7 times) and out the side of the mountain and down a pretty steep down grade back to the city level. Wish I had pictures of it, they may have then on the NMRA web site.
Joe Dawg wrote in news: email@example.com:
In Mt. Vernon, Indiana (not to be confused with Mt. Vernon, IL) there's a crossing where the train goes over the highway and not the other way around. I'm pretty sure the grade is around 10%. It's maybe two miles of track up and down? This is from memory a few years back, so be forewarned I could remember wrong.
As far as long grades, 4% is probably about the steepest you'll see.