When laying track on a curve, has anyone every put a tilt to compensate for centrifugal force like they do on the prototypes? I’m just wondering if it would even be noticeable? Would it have any effect on model operations in preventing derailments?
It is called “super-elevation”, yes, I have tried it on my helix by making the outside of the deck about a 1/4" taller than the inside of the deck. But this helix is a foot wide hand hosts four tracks, so the elevation on each track is perhaps 1/16th of an inch rail to rail. whether the trains like better or knot is anybody’s guess.
Some recommend putting that 1/16th" under every 5th tie or so.
I think the railroads have very specific engineering details for this work. I believe that the rail must be seated perfectly level, that is a block must be used on top of the tie between the tie and the rail, so that the rail bears the weight correctly. Obviously you cannot do this in HO unless you construct your own tracks.
I think it helps in the helix, but out in the open country curves, I think the only reason you would use it is for looks. Railroads had been using super-elevation less with the loss of passenger traffic, most freight does not care about g-forces, but with faster unit trains, it seems to be coming back again.
Or so I am told.
ROAR
I don’t think so. If the outside diameter of the helix is 1/4 inch higher than the inside, and the deck is one foot wide, that means that the rise is about 0.021 inch per inch of width. 1/16 is about 0.062 inch. In my opinion much too high between rails.
The article, Superelevating Ho Flextrack by Richard Stoving in Trackwork and Lineside Detail suggests a 1/16"x1/4" strip underneath the outside rail on curves 48" radius or less.
my problem with this was if i had enough super elevation to look good, long trains would stringline on the curve. this was especially true if i took the slack out too quickly. oh well, life is but a series of compromises and i have decided that i would rather run the long heavy trains than have the super elevated curves. somewhere there must be a happy medium but i couldn’t find it.
Charlie
Bruce La,
I have 34and 36 radius curves on my layout, before I put the track down permanently I shimmed the out side rail with about a little over 1/16 inch cardboard… THEN tested it with all sorts of rolling stock…Found out that double stack tub cars did not play right at all on it,including 85 ft piggyback flats… So I took the shims out and left it flat… So if I were YOU, I WOULDN’T DO IT,
Cheers,
Frank
Bruce, it looks great if it isn’t overdone, and I have seen a lot of it overdone. It does show up in photos, and you will notice it if you keep it to 1/16" or less.
Use strips of cereal box cardstock, or better for water purposes with glued ballast and not wanting the cardstock to swell, use the clear plastic packaging from those items you get at big box stores. You know, the kind that need tin snips or a chainsaw to get into? Between cereal box cardstock or that clear packaging plastic, thin strips placed in the central 5/6 of a curve will have a nice superelevation. So, lay the stuff under the outer tie tips for all but the very ends of the curve, and let the flex track do what it wants on either end. Let the ballast settle around everything as it wants to sit, and under any lifted tie parts, and then glue the ballast. You should get properly superelevated curves that way.
Crandell
My open grid layout has curved subroadbed cut from 3/4" plywood, mostly 34" radii or greater. It’s very easy to add superelevation simply by tilting the risers which support the roadbed, and when done properly, it also offers eased transitions in and out the the superelevation.
Wayne
I used a long piece of wire about 10 ft long to elevate mine, and it looks great and all my rolling stock tracks great. My curve at the end of one of my islands is a 58 and a 56 radius, I was careful to hide the wire right under the rails so it is hard to see with out looking real close. I think the wire was about a 1/16th so after it was under the outside rail it was a little higher. I run long trains some times up to 60 - 70 cars at a time and have yet to string line them. You also have to be careful at the end of the elevation and make the transition gradual or the cars will derail, takes time and patience. Jim.
Using 1/32" or as mentioned the cereal box cardboard will show just enough superelevation but not have any significant troubles running. 1/16" is way too much in my opinion and will result in problems.
SD50s just starting “climb” superelevation at end of easement
F units running same
B&M milk train on siding, purposely laid with waves and crooks to creamery (outward til)
Most all of the clubs mainline curves are done the same and no stringlining issues. I don’t think I would bother w/ superelevation on any radius under 24", you could have problems w some equipment
Unless you operate your Acela, Shinkansen and TGV at speeds measured in Mach numbers, model superelevation is purely cosmetic.
So, how much does the prototype superelevate? The answer is a long, complex equation that accounts for train speed and curve characteristics, different for each curve. So, let’s take a recent example. For the new trackage in New Mexico’s Abo Canyon, BNSF chose 3 1/2 inches, close enough to 1mm in HO as makes no difference, On the curves used that made them satisfactory for speeds from zero to 40mph.
I had chosen to limit my superelevation to 1mm before I learned the above. I also provide nice, long spiral easements into curves, and match the superelevation to the easement to make the entry and exit nice and gradual. With the short trains of free-rolling equipment I operate, that works for me.
Chuck (Modeling Central Japan in September, 1964)
Here’s a shot of the super-elevation I used on my old New Jersey layout:
To my eye, this is just enough to give the appropriate visual effect without being overwhelming. It never gave any operational problems, either, but it’s effect is strictly cosmetic.
Here’s how I super-elevate my curves:
http://www.thecbandqinwyoming.com/Super-Elevating Curves.htm
Very nice, Mark. That much looks just about right to me.
Crandell
So Daytona type banking on curves does not work on trains. Dam I was hoping I could go even faster. Indybob
It WILL work if you get them around tight enough curves at a sufficient speed that they don’t topple inward. I don’t know how the bullet trains handle this problem…
Crandell