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

[www.handymath.com]
Here is a circle calculator for making degree curves.
I read up on this really hard a couole yeras ago.
Civil engineers have two differnt ways of laying out or measuring curves. One is typically for streets and roads the other is for RRs.
The first uses a 100ft arc portion of the curve as a basis point to refernce all other mearuements.
The other uses a 100 foot Cord, or in this calculator it is called an Arc width.

Play with this in ho measuremnts and lay out some curves with it and you will quickly figure it all out and it becomes fun.
So in HO, an 18" radius converted to feet and run theough the formula with a 100foot chord comes to a 45degree curve. Fine for a shay but hell for a rod loco.
I have less than a 12" radius on my hon3 layout. Run that with a 100foot chord and behold the only shay and 2-8-0 blind diver RR.



Edited 1 time(s). Last edit at 07/30/2016 02:22PM by Rich Johnson.