# Radius and space between



## AllenB (Oct 21, 2009)

Regarding HO Scale....When measuring radius, I'm guessing the measurements are taken from the middle of the track correct? And then if for example I have a radius of 28 inches on the outside and I'm running three lines of track around the same curvature, how far apart should those lines be from RR tie to RR tie? Most of my rolling stock will be 50 - 60 footers although on the main line (outside) I may run some passenger cars. 

Thanks!


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## tjcruiser (Jan 10, 2010)

Allen,

HO radius is referenced to the midpoint between rails. (That's not true for all other gauges ... O, for example.)

I spaced my curves a bit more than 2" apart (center to center). That said, I was "winging it" without too much forethought. These specs from NMRA will give you more stringent guidelines, based upon track radii and car Class (length):

Scroll down about half way for HO ...

http://www.nmra.org/standards/sandrp/s-8.html

TJ


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## NIMT (Jan 6, 2011)

Allen, 
I use 2" on the straits and 2 1/4 on the curves, That spacing keeps everything running nicely without cars or engines bumping into each other.


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