I am getting ready to lay HO Code 83 Flextrack on Cork roadbed mounted on plywood in a couple of weeks. I read a posting yesterday that someone used .040 styrene to elevate their curves. As I understand it, this is more prototypical and allows tighter turns. Could someone explain how this is actually done? Things like actual size and shape of cut styrene pieces and where is it placed (under cork or track). I figure that only the outside half of the track is elevated, but I am not sure. One concern is if one side of the track is higher will this cause track distortion over the long term? My other concern is that I am a very beginning level MRR and I am concerned that in my inexpierence I may be trying to do something that is beyond my abilities.
I tried locating this in the data base but could not find anything useful. Thank you for any help you can give.
I use strips of cardboard from a Walthers kit box and cut it in strips with my hobby knife and slide it under it under the ties, run all my engines around the the curve to make sure they all like it. Once you lay down the ballast it covers up the strips.
Its best just to raise the outside rail on a curve for high speed main lines. Cardboard strips can be used like the first reply suggested. Start the elevation just before the curve. It also works better if there are easements from straight to curve. If there are no easements then super elevation can cause problems with string lining long trains as they transition from straight to curve. Only your broadest curves should be super elevated. Super elevated tight radius curves will only lead to problems. Building in Easements are a better way to go. There are some good track laying tips on the MR site. At the top of this page is the how to drop down menu. There are loads of tips and tricks for you.
Superelevation actually requires bigger radius curves when you consider passenger car diaphragms and excess height cars. The tops will actually get closer together then the bottoms.
You can ease into your superelevation as you use easements. For example you can use .010 on the easements and increase to say .030 for most of the curve. BTW, .040 can be a lot of superelevation.
The size of shim stock is not the only variable to consider when elevating. For example, if you have a .040 shim and you put it under just the tie portion outside of the rail, you will get a certain amount of lift. If you push the shim under, past the rail to almost half way, the outside rail will lift even further. I prefer the shim just under the outside rail to keep from having flex problems.
Be sure and run trains a while before ballasting since you may want to change the superelevation.
After cutting and fitting a section of flextrack into place (before gluing it down, I slide a piece of styrene (I use “For Sale” signs from Walmart) under the track. Trace along the outer edge of the ties. Draw a curve parallel to that line about an 1/8th" to the inside of the original line. Cut out the pattern. Slide it under the track and mark it’s location. Glue it down (I use a thin layer of acrylic caulk). When you’re ready to glue down the track, put a thin layer of caulk on the strip, and where the inside of the rails will be. I use map pins to hold the track in place while the caulk sets up.
It is about as much physical work, but quite a bit faster, to merely plane your roadbed so that its inner edges are somewhat lower than the outer. You can sand or use a surform file.
Less is more with super-elevation. It is too often overdone and looks odd. So, try to keep the actual disparity between the opposite tips of the ties to something less than the 0.040" you were thinking about. I would try 0.030" first and see if you like how it looks.
The photo below shows 0.035" superelevation and is almost too much.
One more little trick that I use is having a small level like this one. After you determine the degree of your super elevation, place the level on that spot and mark where the bubble is with a pencil. As you go and after your done just slide the level slowly along the track watching the bubble closely. You can easily see where any inconsistencies may be. It works surprisingly well in showing the transition areas and how smooth they will be. Good luck. [C):-)]
Could I ask you to elaborate a little bit more about “tight” vs “broad” curves. Most of my curves are approx. 26" without easements. I have tried very hard to add easements but with the exception of two broader curves they just won’t fit in the space I have. Is a 26" curve without easements too tight for superelevation? If it is not, what height would you reccomend for the shims?
Superelevation does not allow tighter turns on the model, just the opposite, usually. If you are a beginner, getting flat curves to work perfectly might be a better (and more rewarding) goal.
In model railroading, superelevation is cosmetic only and very easily (and often) overdone.
The physics of our models differ greatly from their real-life counterparts.
I have Code 83 track layed over top cork road bed. I have very large radius curves and I run 70MPH stackers over it. I believe the trains run better over the curves when the outside is slightly elevated. to acheive this a use very thin pieces of construction paper or styrene underneath the outside edge of the cork. You just have to play with it and make it look at life like as possible. I dont elevate the outside egde of my curves on industrial spurs and yard tracks of course. You are only limited to what you can achieve as a modeler if you tell yourself you dont have enough experience. Trial and error is the one of the best parts of this hobby!!!
On my layout, I superelevated just a few curves, only after it was apparent that those spots would only work smoothly if they had a bit of superelevation. I used the try, try again method to establish how much to raise the outside rail. Generally that worked out to approximately about a half tie thickness at the highest point . Taper the superelevation upwards towards the apex of the curve and then back down again. Like many things , this is the type of learning that comes after finding all of the wrong ways to do it, thus leaving success as the only available answer. Good luck with your trackwork!
First thing, superelevation in model railroading is purely cosmetic. Unless you operate your model Acela as speeds measurable in Mach numbers, it isn’t necessary.
Second, proper superelevation is not much. On the new construction in Abo Canyon, BNSF is only superelevating the outer rail 3.5 inches above the inner rail - about 1mm in HO scale.
Third, superelevation should always be used in conjunction with easements. From dead level at the true point of tangency, the superelevation should increase gradually until reaching its full height at the true point of curvature. Just as the spiral easement prevents an abrupt change from tangent to curve, using the full length of the easement as a ramp for superelevation prevents an abrupt change from level to superelevated track.
In my opinion, and John Armstrong’s, spiral easements are much more important to smooth operation than is superelevation. With curve radii above 24 inches, reducing the radius 10mm and incorporating a smooth easement half a meter long will do wonders for smooth operation.
Chuck (Modeling Central Japan in September, 1964 - with spiral easements and superelevation)
