Degree of grade for curved track

Discuss park gauge trains and large scale miniature railways having track gauges from 8" to 24" gauge and designed at scales of 2" to the foot or greater - whether modeled for personal use, or purpose built for amusement park operation or private railroading.

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Springhill-RR
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Degree of grade for curved track

Post by Springhill-RR »

We are rebuilding a 2 ft. gauge track. What degree of angle across the 24" should it be? I hope I am asking the correct way. Should the outside rail be about .25" higher that the inside rail? We operate at low speeds.
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kcameron
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Re: Degree of grade for curved track

Post by kcameron »

Your correct term would be 'super-elevation' aka banking the curve like higher speed roads. Depending on the speed, it would change. Many feel that for model tracks, the speed is low enough to not require it. The other consideration is that if you have super-elevation on a curve, decide to stop on that curve, you are tipping a bit. Depending on the cars, loads, or riders, this could be a problem if you have any significant super-elevation.
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rkcarguy
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Re: Degree of grade for curved track

Post by rkcarguy »

I would lay the track with minimal (1/8") to zero "super-elevation" or banking. Real railroads add this to their lines because it allows them to move 1000's of tons of freight and passenger trains trough curves at high speeds.
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Erskine Tramway
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Re: Degree of grade for curved track

Post by Erskine Tramway »

We had a speed restriction of 50 mph on Moorcroft Hill, account they couldn't superelevate for the otherwise 60 mph track speed. If they'd done the higher super for the mtys, the coal trains going up the hill at 10-15 mph would have been leaning over too far. When I rode the Southern Crescent from Birmingham to DC, the Conductor told me the same thing, though in their case they couldn't super for passenger speeds account the tri-level auto racks would be leaning over too far.

On a 'riding' scale railroad, you're not likely to be running fast enough for it to matter.

Mike
Former Locomotive Engineer and Designer, Sandley Light Railway Equipment Works, Inc. and Riverside & Great Northern Railway 1962-77
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Steggy
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Re: Degree of grade for curved track

Post by Steggy »

Springhill-RR wrote: Wed Jun 02, 2021 8:03 pmWe are rebuilding a 2 ft. gauge track. What degree of angle across the 24" should it be? I hope I am asking the correct way. Should the outside rail be about .25" higher that the inside rail? We operate at low speeds.
Riding scale cars have very high centers-of-gravity relative to the equipment's physical size. Whatever benefit superelevated ("banked") track might offer would be negated by increased tipsiness on curves due to the bulk of a car's mass (the passengers) possibly being over or inside the inside rail of the curve. The reality is most such railroads are not run anywhere near a speed where a banked curve is of any value. I would lay the track as flat as possible, with no more than 1/8" height difference between inside and outside rails in a curve.
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Kimball McGinley
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Re: Degree of grade for curved track

Post by Kimball McGinley »

I agree, just keep it flat. One benefit is that you will not need to remember how much super-elevation you have in each curve. Just need a level, no measuring, or shims, etc. Easy-peasy!
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kcameron
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Re: Degree of grade for curved track

Post by kcameron »

One guide I use the bubble in the level. I go for anything that hits between center and touching the outside line. Idea is to be flat or if anything, a hair high on the outside of the curve, never high on the inside of the curve.
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Rich_Carlstedt
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Re: Degree of grade for curved track

Post by Rich_Carlstedt »

Its a function or Track Radius, as well as anticipated train speed
Larger radius tracks need less
Rich
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