# Superelevated track



## JackM (Jul 29, 2008)

I have made very good progress in building my flowerbed loop in order to have something to run my RDC on before the snow flies. In creating an elevated curve at one end (15' diameter) I realized that I was accidentally tamping it down just like a NASCAR track (a left turn!) only not so extreme. This should look very cool when the RDC pops out from behind some unidentifiable green plant. But I'm not sure just how steep I should bank it. Does anyone know what degree of tilt the big people use? For that matter, how much tilt is too much? No sense having the RDC come sliding into the station on its side.

Thanks,
jack

Yes, I realize the RDCs don't exactly do Acela speeds.


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## East Broad Top (Dec 29, 2007)

Not much, if at all for most railroads. The only lines that would have superelevated curves would be highly traveled, well-maintained mainlines. Branchlines wouldn't have any. I've got a B&O standards book at home which has that info, I'll check later on tonight. I seem to recall it being very slight--a matter of an inch or so difference between rails. My personal opinion is that it just looks "wrong" in the garden setting. There are two reasons. First, it just doesn't scale well. The aesthetics of broad, sweeping mainlines don't translate to the average garden. Second, there's the issue of a foundation for your track. To keep the superelevation in check, you're going to need a very solid subroadbed--one free from the forces of expansion and contraction which will invariably twist your track one way or the other off level. Within short order, it won't look like proper superelevation, rather just bad track. 

Later, 

K


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## Totalwrecker (Feb 26, 2009)

I use it on my trestle...2-3% max ....eyeballed. 
I did that just so trains would lean inboard... when the little ones get the throttle it's a good thing. 

The RDC did run on banked track, but they'd be more likely to roll down an embankment than slide into home... lol 

John


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## tacfoley (Jan 3, 2008)

I agree with Mr K - super-elavated track was discussed over on the Gauge 1 forum sometime back. Bearing in mind the starship speed at which many folks seem to run their Gauge 1 live-steam trains, it would have seemed, at first glance, to have been a good plan.

However, the scale super-elavation for G1 track was so small as to be almost invisible to the casual observer, and even scaling it up for 1/20.3 or similar it is still miniscule and, to be frank, a waste of effort.

I have two complete circles of track - 25 and 26.5 feet in diameter - and although I run Gauge 1 stuff at a respectable speed, something around a scale 60mph for a passenger train, it has yet to go flying into next-door's fence due to lack of super-elevation...

Spend your energy on getting a sound trackbed instead - THAT'LL pay dividends later on.

tac
www.ovgrs.org


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## East Broad Top (Dec 29, 2007)

In looking at my B&O standards book, the absolute maximum superelevation they allow is 7.5" (Being the difference in height between rails). Alas, that's garnered from a table for track clearances, not one showing how much superelevation would be used for which degree of curvature or track speed. In 1:32, that's around 5mm at the highest superelevation. If you consider that to be an extreme (i.e., high speed and fairly "tight" curve, then the average superelevation would be in the neighborhood of 4" or so, which in 1:32 is 3mm. There are mathematical formulae for determining superelevation based on degree of curvature, speed, etc. that you can find on the web if you search "track superelevation." I offer this merely as mental fodder for those interested. My opinion on how it translates in the garden has already been noted. 

I will offer this - railroad was fine-tuned 5 weeks ago for the National Garden Railroad Convention, where I went through with new ballast and made darned sure everything was level. A mere 5 weeks later, and I've got tracks leaning one way or the other thanks to the forces of expansion and contraction working the ballast. You can do superelevation if you'd like, but you're going to need rock solid (i.e., concrete) subroadbed to keep it aligned. 

Later, 

K


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## JEFF RUNGE (Jan 2, 2008)

I like a little super elevation in the road bed, about 1/4" across 2 ft., more important then the amount is the consistency through the curve. This works well on 40 ft dia curves at speeds up to 100smph


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## Totalwrecker (Feb 26, 2009)

The time with a belt sander on the stringers didn't take long, I got the look*I * wanted. It was a one time deal.... 
My fast frieghts run at 25 -35 smph and the crack varnish at 40 smph...yeah I don't see a difference betwee the rails, but I do see the train do a slight lean and that's what I wanted. 

John


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## Totalwrecker (Feb 26, 2009)

Posted By Totalwrecker on 14 Sep 2009 12:23 AM 
The time with a belt sander on the stringers didn't take long, I got the look *I *wanted. It was a one time deal.... 
My fast frieghts run at 25 -35 smph and the crack varnish at 40 smph...yeah I don't see a difference betwee the rails, but I do see the train do a slight lean and that's what I wanted. 

John


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## tacfoley (Jan 3, 2008)

Posted By East Broad Top on 13 Sep 2009 09:03 PM 
In looking at my B&O standards book, the absolute maximum superelevation they allow is 7.5" (Being the difference in height between rails). Alas, that's garnered from a table for track clearances, not one showing how much superelevation would be used for which degree of curvature or track speed. In 1:32, that's around 5mm at the highest superelevation. If you consider that to be an extreme (i.e., high speed and fairly "tight" curve, then the average superelevation would be in the neighborhood of 4" or so, which in 1:32 is 3mm. There are mathematical formulae for determining superelevation based on degree of curvature, speed, etc. that you can find on the web if you search "track superelevation." I offer this merely as mental fodder for those interested. My opinion on how it translates in the garden has already been noted. 

I will offer this - railroad was fine-tuned 5 weeks ago for the National Garden Railroad Convention, where I went through with new ballast and made darned sure everything was level. A mere 5 weeks later, and I've got tracks leaning one way or the other thanks to the forces of expansion and contraction working the ballast. You can do superelevation if you'd like, but you're going to need rock solid (i.e., concrete) subroadbed to keep it aligned. 

Later, 

K 
And that, Sir, is precisley what one French manufacturer achieved with his pre-cast concrete trackbed sections that had curves like an automotive test track.

That and the ambitious pricing made sure that the product has not been seen much recently.

tac
www.ovgrs.org


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## Greg Elmassian (Jan 3, 2008)

Posted By JackM on 12 Sep 2009 05:18 PM 
I have made very good progress in building my flowerbed loop in order to have something to run my RDC on before the snow flies. In creating an elevated curve at one end (15' diameter) I realized that I was accidentally tamping it down just like a NASCAR track (a left turn!) only not so extreme. This should look very cool when the RDC pops out from behind some unidentifiable green plant. But I'm not sure just how steep I should bank it. Does anyone know what degree of tilt the big people use? For that matter, how much tilt is too much? No sense having the RDC come sliding into the station on its side.

Thanks,
jack

Yes, I realize the RDCs don't exactly do Acela speeds. 

Of all the loco available from Aristo and USAT, the RDC is one of the most sensitive to "twist" or "warp" in track. You will get this entering a curve with superelevation. In real railroads, there is a transition from level rails to the superelevation, and it begins before the curve. This is very hard to maintain in a garden railroad, and takes more "track length" than most people realize.

I would advise against this until you get your railroad very reliable, i.e. you can run your longest train for hours on end without derailments, you can back up trains, etc. After that, if you want to add this visual enhancement, go for it.

I have seen countless people try this and have layouts that have operational issues.

This is definitely something I would NOT recommend to a beginner.

Regards, Greg


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## JackM (Jul 29, 2008)

Thanks for the input, guys. This idea will go on the back burner for a while; got better things to think about.

jack


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## aceinspp (Jan 2, 2008)

For info the most elevation allowed by FRA standards is 8 inches class 1 and 2 and 7 inches for 3 to 5. I also would not recommend using elevations as figuring the spiral elevation entering and leaving the full body of a curve would be a pain to even try to install and then try to maintain it. The long cars like the RDC would tend to derail when exiting a curve without the correct spiral elevation. Later RJD


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## neals645 (Apr 7, 2008)

For the mathematicians in the group (or the curious), the proper superelevation for any curve can be mathematically calculated. The formula is given by Glenn R. Peterson in "Superelevation and Transition Spiral Primer" (this paper used to be posted on the web but I can nop longer find it). 

"To compute the required superelevation, use the following formula: 

E = (S x V x V) / (R x g) 

where: 
E is the equilibrium superelevation in the same unit as the rail center-to-center spacing (see next), 
S is the rail center-to-center spacing in any linear unit, typically given in mm or inches (for crowned rail of average 
profile, this is about 1.04 to 1.05 times the track gauge), 
V is the train speed in meters / second or feet / second, 
R is the track radius in meters or feet, and 
g is the gravitational constant: 9.80665 meters / (second * second) or 32.17405 feet / (second * second). 

Note that V, R, and g must be either all metric or all imperial. E and S are in the same linear units. To 
convert miles per hour (MPH) to feet per second (FPS), multiply MPH by 22/15." 

This formula gives the amount of superelevation required to exactly balance the centrifugal force of the train. You have to know how fast the train will be going - if faster it will tend to tip toward the outside, if slower toward the inside. Peterson recommends using a speed that's about 80% of maximum. 

The paper is written with 7 1/2" gauge in mind, not G gauge.


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## aceinspp (Jan 2, 2008)

Here is the 3 inch unbalanced equation should someone care to compute it out for 1/29. This is what is used by the Railroads. There is also a 4 inch unbalanced formula used to compute for Amtrack. Later RJD


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## Semper Vaporo (Jan 2, 2008)

I can't resist!


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## aceinspp (Jan 2, 2008)

Yep I can't resist either maybe you should go for the super elevated track.







At least no worry's except if you derail. Later RJD


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## eheading (Jan 5, 2008)

I hate to admit this, but when I first saw the title of this thread, that is exactly what I thought was meant by "superelevated" track!!!

Ed


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## aceinspp (Jan 2, 2008)

Now Ed I don't think you where actually thinking that crazy post was what we were talking about here do you? Man I'm going to have to come back down and give you a couple more classes.







Later RJD


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## eheading (Jan 5, 2008)

You are overdue, RJ!!

Ed


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## Greg Elmassian (Jan 3, 2008)

C.T., I want some of what you are smoking! 

hahaha... good one! 

Greg


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## Semper Vaporo (Jan 2, 2008)

I'd be more than happy to share... but only if you REALLY, REALLY want it!

It is really powerful stuff... beyond anything you might imagine!

Perfectly legal, but also very controversial!


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