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superelevation-is it worth it?

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superelevation-is it worth it?
Posted by Anonymous on Monday, October 29, 2001 6:09 PM
I am getting ready to lay track and was wondering if anyone has had experience with superelevating the track , good or bad. I am wondering if it would be worth it or if the height is not exactly perfect will it cause more harm than good. Any opinions? Thanks.
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Posted by sumpter250 on Monday, October 29, 2001 7:37 PM
In a word, no.
You didn't mention what scale. If you're in G scale, then you might consider using superelevation. It is great to look at, but if done to actual scale you can hardly see it,if done so you can see it,there are some problems.
Basicly, model trains don't have the same inertial dynamics as the prototype. The model curves are sharper than the prototype, and the model trains have a tendancy to "fall"into the curves, even when the curve is laid flat. Centrifugal force doesn't effect the model as it does the prototype. So, if you tip the curve inward (superelevate) you increase the tendancy for rolling stock to "fall"into the curve. Double stacks, and auto racks WILL, guaranteed. As we rebuild curves on the club layout,we are taking the superelevation out. Operation has already improved.
Pete
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Posted by Anonymous on Monday, October 29, 2001 9:44 PM
Superelevation can look great when used with easements. The change for superelevation should begin with the start of the easement and reach it's maximum with the start of the fixed radius. I don't have experience with the high center of gravity mentioned by the previous reply as I model the 50's and place my weight as low as possible in the cars.
An advantage of superelevation is that it effectivly increases the radius of the curve.
I personally like superelevation and if used properly it should not cause any problems. I use a 30" minimum radius mainline and the club I belong to uses a 54" minimum for double track mainline.
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Posted by Anonymous on Monday, October 29, 2001 9:58 PM
Now this is only my two cents, but...

Trackwork is difficult enough to do correctly on a flat surface. Even tiny mistakes can be drastic when measured in the scale you model in. Any design element you add to further complicate a design necessitates a higher level of precision in executing that design. This means the potential for mistakes not only increases but the margin of error decreases. Also, variables like temperature can wreak havoc on trackwork.

Superelevating a curve is a very real and practical solution for real railroads or highway departments. But honestly, I don't think it would serve any purpose on a model (unless it was a very large model operating at a high rate of speed). However, if you are dead set on modeling a superelevated curve, you should be acquainted with a few of it's characteristics.

Spiral (or easement) curves: these are the transition areas between the tangent (straight section) and the circular curve. This is a parabolic curve.

Runout: the change from flat to superelevated. Typically the runout occurs in the spiral portion of the curve, not in the circular curve. Just as the radius of the spiral curve is steadily changing, so should the cross-slope change throughout the runout.

Cross-Slope: the change in elevation from one railhead to the other measured perpendicular to the centerline of the track and divided by the distance between the railheads. This is usually expressed as a percentage (i.e., "x" vertical feet per 100 horizontal feet).

Although the design speed and radius of the curve dictate the runout length and cross slope, a general rule is the length of the spiral in and spiral out is usually about 1/3 the total delta of the curve. And a typical cross slope would be between 2-5%.

Whatever you do to construct this type of curve, be consistent. Aberrations will be obvious to your rolling stock but might be insignificant to the eye. Good luck if this sounds like something you'll try.
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Posted by Anonymous on Wednesday, October 31, 2001 1:21 PM
I just finished laying the mainline, and i superelevated all of my curves. I used balsa wood, thin strips put underneath the outside rail. I haven't had any problems whatsoever, and it really gives the trains that look when they lean into the curve. I model in HO and it was pretty simple. There is an article on it in Trackwork And Lineside Detail put out by Kalmbalch. To me, it was really worth it.
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Posted by Anonymous on Friday, November 2, 2001 5:50 PM
I am thinking of doing the same thing when I start to lay my track. But I also welcomed the other opinions and read them carefully. I would think that one way to test this before the "finished" track is down is lay some track down with a curve on a temporary flat board, elevate the curve and then run a short train across to see if there are any problems.
Maybe the height of elevation is something to adjust and test in order to get the right "lean" without the cars falling over.
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Posted by Anonymous on Saturday, November 3, 2001 8:40 PM
Is it worth the trouble? You bet it is, in my opinion!
As others have stated, you need to be consistant and it should be done with transitions, but the visual effect is dramatic. If you ever plan to photograph your layout, the effect becomes even more dramatic - especially when you see a long train lean in both directions through a beautiful S curve. It really can be seen in some of the Allen Keller videos.
I have built or helped build at least four good sized HO steam-era layouts with superelevation. We have generally not exceeded a 1/8" slope, but even 1/16" is notecable. These have generally been on 30" radius curves. We have experienced no operational difficulties with superelevation but have observed the above caveats. We also are fussy about maintaining free-rolling trucks and try to observe low centers of gravity on our rolling stock. With this, we find we do not have to be too fussy about maintaining the NMRA minimum weight recommendations.
We also have run helpers and reverse moves on superelevation in mountain districts without difficulty.
The purpose of superelevation in model railroading is purely cosmetic but, it is very visible on the prototype and the effect can have a very positive impact on the realisim of our models as well. I have seen several good articles on different methods of implementing superelevation in the hobby press. I feel its worth the effort.
Jim
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Posted by Anonymous on Monday, November 5, 2001 1:47 AM
It depends on:
(a) if you are willing to do a bit of extra work for a better appearance in your trackwork;
(b) your era;
(c) how strict do you want to be to the prototype.

Most prototype railroads have removed or are removing super elevation on curves. Reason: to reduce maintenace. Super elevation was great on track used by passenger traffic because there was less "jerk" entering a curve. Benefits to freight traffic are not enough to warrant the increased cost of track maintenace.

Peter

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