Minimum distance between tracks? HO?

Model Railroader Layouts and layout building
1

What is the NMRA standard for minimum space between parallel tracks in HO from centerline to centerline?

Very difficult to find this stuff on the NMRA site.

Thanks in advance.

2

I think it is 2 inches if I remember correctly. What you need to look for at the NMRA site is the Standards and Recommended Practices. They should be associated with trackwork. As far as I can remember, all the scales are on one document, so you have to look through it. It may be helpful to download it and print it out and keep with your layout. That’s what I did.

3

The distance depends on curvature and the type of equipment negotiating those curves. If you are running a Challenger pulling long passenger cars, and your curves are near 28", you will want something near 3" between centers. This is because units on the two tracks could sideswipe one another, causing real damage and derailments.

4

NMRA Standard S-8. Here is the link:

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

Jim Bernier

5

Thanks a lot.

My point exactly: why was this so difficult for me to find?

cheers,

6

I’ll play.

Why couldn’t you pick the “Standards and Conformance” link? and then the Standards link?

7

Hi!

I’m a long term NMRA member and applaud their issuance of standards and thank them for their leadership in the hobby!

Their spacing/clearance standards are great, but one must remember these are “minimums”. I personally start out with those spacings, but almost always have widened them. There are two primary reasons for this, one is to assure more adequate clearances of longer cars on curves, and the other is to allow the ol 0-5-0 “switcher” to access cars on crowded sidings and yards.

Put another way, start with the NMRA standards and “go wider” as needed to fit your personal preference. Trust me - been there, NOT done that!

Mobilman44

8

I tend to agree with Mobilman on this subject. Close clearance on straights look good from above. But like he said the 0-5-0 needs room and also for flat switching yards you may want read car numbers or have wide loads.

Our module standards in the club is the 2 outside mains have 2 inch space and the third main is a 3 inch space that makes it easier for switching.

Pete

9

I strive for realistic appearance and prefer really big curves (60"r. and up) and turnouts. While 13’ centers might be good for parallel tangents I like to go 16’ or even 20’ centers on curves. Remember, too, that easements really help control overhang. jc5729 John Colley, Port Townsend, WA

10

If you use the same radius for both inside and outside curves, the spacing will be greater in the middle of the curve than at the ends.

This example uses 30 inch radius.

11

You can get the same result by using concentric curves, but making the spiral easements to the inner track longer and giving them a greater offset.

Some specific dimensions, modeling in 1:80 scale:

  • Curve radii, 610 and 670mm (60mm spacing).
  • Tangent track spacing, 50mm.
  • Outer track (normal) easement, 500mm length, 10mm offset.
  • Inner track easement, 800mm length, 20mm offset.

This has the advantage that there’s no reduced clearance ‘pinch point’ at the place where the curves meet the tangents.

Chuck (modeling Central Japan in September, 1964)

12

I guess I just find the stands a little difficult to navigate.

thanks again