With plywood sub-roadbed on open grid framework, it's easy to add superelevation: simply fasten the risers to the underside of the roadbed, elevate the roadbed to the height required, then, at the mid-point of the curve, push the bottom end of the riser to the outside of the curve. The farther you push, the greater the degree of superelevation. Fasten this riser to the benchwork, then raise the risers at both ends of the curve to the desired elevation, and keeping the risers perpendicular to the bench work, fasten them in place. Now, fasten all of the other risers in place, at the proper elevation, where they sit and at whatever angle from perpendicular that they're located. This will give you a natural transition through the curve, from no superelevation at either end to full at the mid-point of the curve. I set mine by eye - most of the curves have a 30 mph speed limit, although that in the second photo is 10 mph for passenger trains.
Wayne
Unless you are trying to run Acela at prototype speed on toy train radius curves, superelevation for models is purely cosmetic.
That said, if you want to have prototypical superelevation, you should also have spiral easements into your curves. Starting with dead level at the point of tangency, the outer rail should rise in proportion to the decreasing radius, reaching its (modest) maximum at the point where the curve radius becomes constant.
Why the inserted, "Modest?" My prototype had tight curves (though not as tight as those on my layout.) It also had a freight train speed limit of 70KPH (43.5MPH,) and posted slower speeds on the worst curves on a line which was built using a sidewinder for a straightedge.
I am superelevating my curves - a maximum of 1.5mm, or slightly less than 1/16", from one end of a 28mm tie to the other. This results in a tilt of 3 degrees, enough to give the impression without putting the rolling stock at risk.
Just my . Other opinions may differ.
Chuck (modeling Central Japan in September, 1964)
There is probably no practical reason to use superelevation but it does look good. The amount depends on the curve radius, and definitely use transitions. 1/16"T x 1/8"W strips of cardstock worked well for me on 30-36" radius curves. This a about .0625" - 5.4" in HO scale. I run 20-25 car trains. (inflation).
Karl
The mind is like a parachute. It works better when it's open. www.stremy.net
If you look at the tilt on the Duplex in my avatar at left, it seems as if the engine is heavily tilted. That is because it is heavily tilted, and quite a bit more than I had anticipated or wanted. If you can accept it, I have very little superelevation in the roadbed and the track is caulked tight to the roadbed. The rest of the tilt is done by the engine due to slop in the drivetrain. This would depend on the model, I am sure, but I wanted to let you know that you will find superelevation can be overdone in terms of its visual appeal in some circumstances.
Go lightly, mock it up with some track nailed down temporarily, and then watch all your engines come around the curve. If the list is pronounced, it will not look so good. Moreover, it won't be great for performance on a model railroad. It would be much better to have your engines tilt less.
Precision Scale Company makes HO flex track with studs under one end of the ties so that it is super elevated. (Obviously ya gotta bend it the right way for this to work!) The Walthers catalog shows that the track is not currently in stock. I bought mine at a train show.
I have used it on my layout and am pleased with the results although it is a challenge to ballast -- and the transition into/out of the superelevation is also tricky. Unless it is gradual it is a tracking challenge and also a challenge to the couplers and diaphrams on passenger cars.
Visually it really looks neat to see full length passenger cars and C&NW E units lean into curves, just as I remember them doing as a kid through my old home town of South Milwaukee WI.
Dave Nelson
td,
Banking is called superelevation. RRs would do that so that trains could run faster on mainlines around curves. If your mainline will be for running high-speed freight, superelevation would be "appropriate" looking but it isn't necessary.
The question of how much. I read an article recently that stated for HO .030" is the maximum height you want to go. This can be achieved by gluing styrene shims to the underside of your rail ties (on the outside end of the tie) that run perpendicular to the ties.
When superelevating a curve, you want to shim it so that it gradually increases along the curve - i.e. start with .010" shim for a portion, then increase it to .020", then to .030". (Same for decreasing when you're coming out of the curve.) And you actually want to start and stop the superelevation just slightly before and after the curve.
td, it's entirely up to you how much you want to superelevate or whether you want to do it at all. If you do but only want to go .010" or .020", that's okay. The visual effect will still come across.
Tom
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