I was wondering what are all the advantages/disadvantages of superelevated tracks. I understand that on mainlines when train is going at higher speed the S.E. tracks help the train around curves and puts less strain on the coupler. I also agree that when a train is speedng along and goes around one of these curves it looks great! But what about curves in staging? Where a person might not see them. I'll be running a small branchline and logging ops with a hidden staging under logging area. IYO do you think I should elevate the curves under there? Also the speed that I will be running will be on the slower side.
In the model railroading world, super-elevating curves really serves only one purpose : to create a realistic visual effect. However, due to the scaled down nature of our models, super-elevating doesn't add much to keeping a train on the rails while speeding around curves since we're dealing with far different (and much smaller) physical forces than in the real world.
On prototypical railroads, super-elevation was not used in yards since speeds are so low. Generally, they were used only on mainlines, especially in sections where speeds were higher.
While I don't know much about logging operations, it would seem to me to be a waste of resources (ie: money) to engineer super-elevated curves for slow-moving logging trains on tracks not meant to be permanent.
If I were you, I would keep super-elevated curves where they will provide the greatest visual impact -- on your branchline -- and not in your hidden staging areas or logging area.
Super elevation implies a 6" or greater change in track alignment. On model railroads, that would be greatly unnecessary unless you're modelling the Acela on the NEC.
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GraniteRailroader Super elevation implies a 6" or greater change in track alignment. On model railroads, that would be greatly unnecessary unless you're modelling the Acela on the NEC.
In the early twentieth century at least, super elevation was normally limited to a maximum of 6 to 8 inches. Unfortunately, only if train speeds are uniform can an ideal amount of superelevation be determined. Excessive superelevation creates additional train resistance. "An instance is recorded where two engines hauling 3500 tons of coal on an 8-degree 30-second curve with a central angle of 185 degrees habitually stalled when the super elevation was 5.5 inches, but when it was reduced to 3 inches, no further difficulty was experienced." (Williams, Design of Railway Location, 1924)
Superelevation for our models is merely for appearance, not operation. When used, it should be no more than what is noticeable yet subtle. Too much superelevation can cause derailments, particular where the transition to/from superelevation isn't smooth and gradual. Also, superelevation creates a greater opportunity for "string-lining" (cars flipping into the inside of the curve) on long, heavy trains.
MPRR Where a person might not see them. I'll be running a small branchline and logging ops with a hidden staging under logging area. IYO do you think I should elevate the curves under there? Also the speed that I will be running will be on the slower side.
Where a person might not see them. I'll be running a small branchline and logging ops with a hidden staging under logging area. IYO do you think I should elevate the curves under there? Also the speed that I will be running will be on the slower side.
No, not for either visible or hidden portion of your layout except perhaps for visible sections of the branchline if trains operate at speed, for reasons previously mentioned by myself and others.
Mark
Using transitional curves between straight and curved track has very desirable effects for both operations and appearance. This aspect of track alignment should be used on both hidden and visible track.
markpierce Using transitional curves between straight and curved track has very desirable effects for both operations and appearance. This aspect of track alignment should be used on both hidden and visible track. Mark
I agree entirely. If anything, spiral easements are MORE important on hidden curves, where you want your trackwork to be as derailment-resistant as possible.
That said, superelevation on hidden trackwork is unnecessary unless you run trains at speeds measured in Mach numbers. Even an HO scale N&W J running at its usual (90mph) speed is only traveling a tad over one full scale mile per hour.
Chuck (Modeling Central Japan in September, 1964)
I will be superelevating all of my visible curves but not any hidden curves, since (as stated above) it is just a visual feature on a model railroad. Here is a one minute video I did on my N-scale test layout showing the visual impact of superelevated curves:
http://www.youtube.com/watch?v=5LmWU8W3K1I
Jamie
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