Re: curve and grading rules on the D&RGW and other Colorado NG

The tightest curve allowed on the D&RGW and RGS narrow gauge routes was 24 degrees. This works out to a curve with a radius of 239 feet. In HO that works out to a 33" radius curve! Most model railroads have to stick to 22" and tighten down to 18" which translates to 35 and 44 degrees respectively. This explains why your wheels drag on the cars' underframes!

As to grades, 4% was the common maximum but the Monarch Branch had, IIRC, 4.5% on the switchbacks. The Uintah RR had 7% grades and 66 degree curves and used Shays and articulated 2-6-6-2T locos.

To figure out what a degree of curvature is for a given radius in scale feet, divide 5729 (the radius of a 1 degree curve) by the known factor to get the other. 5729 divided by 239 scale feet = 24 degrees (23.97 actually). 5729 divided by 24 degrees = 238.77 feet of radius.

I gotta do a 5729 stock car.



Edited 1 time(s). Last edit at 07/26/2016 09:10PM by Herb Kelsey.