Parallel Track Spacing

Model Railroader Layouts and layout building
1

I would like information about recommended spacing of track for HO…Straight track and on curves?

Any help would be appreciated and recommended literature for layout building and DC wiring

Thanks

RALWAB

2

National Model Railroad Association

https://www.nmra.org/standards

Kakmbach Store downloads

http://www.kalmbachstore.com/modeltrains-railroading-model-railroading-digital-downloads-downloadable-articles-dc-wiring-and-digi.html

Kalmbach store books

http://www.kalmbachstore.com/modeltrains-railroading-model-railroading-books-basic-book-series.html

3

Straight track is normally 2 inches on center and curves are approximately 2 1/4 inches.

Rich

4

Also see HO Atlas Track spacing-on-center for curved sectional track radius. Thus, the radius chosen by Atlas is conservative spacing – So locos & cars won’t side-swipe each other.

5

2 1/4" is not one-size-fits-all for track-to-track HO spacing on curved tracks. It will be too close on the tighter radii many modelers use – especially if they are trying to run longer equipment. The NMRA track-to-track spacing standards referenced earlier are a much better guide, varying by both curve radii and equipment size.

Byron

6

The best way to determine spacing of two parallel tracks on curves, is to make a template of the desired curvature of the outer track. Make a strip of cardboard and bend it to represent the center line of the outer curved track of the desired curvature. Make two other strips of cardboard that is the length and width of the longest passenger car or loco. Place this strip across the curved strip. This gives you an idea of the overhang of the longest car or loco. The ratio of the length of the curved track to the length of the longest car is called the “Easement”. From your complete template, you will be able to determine the curvature of the inner curved track,such that the longest cars will not bump cars on the inner track. Do the same for the inner track curvature to make sure that long cars will not bump structures. Still easier would be to use two longest cars on curved section of flex track. Bob Hahn

7

That’s not the way the term “easement” is typically used in real-life or model railroading. An easement is a gradual transition from straight (tangent) track to the curve. Here is an explanation of model railroad easements from this site. They look like this:

When answering questions from newcomers especially, I think it’s helpful if we try to use terms the way they are typically defined in the hobby.

Byron

8

Part of the ‘proper’ track center distance equation is looking at the prototype (Surprise!)

Up to the transition era, 14 foot center-to-center distance (49mm in HO) was normal on main line tangent track. More recently, as bigger rolling stock and newer safety rules have come in, the distance has widened to 21 feet and more.

The best way to determine lateral clearance requirements on curves for YOUR rolling stock roster is to lay a few lengths of flex track to various concentric radii and put your models on them, Using 0-5-0 propulsion makes clearance checking sure and painless. Since one modeler might have a roster of ore jimmies and 0-6-0Ts, while another pulls his Schnaebel car with an accurate model of N&W 2300 (aka Jawn Henry) it should be obvious that one size does not fit all.

My own standard is for parallel tracks to be 50mm apart, while my concentric curves are 60mm apart. I achieve the spread by using longer easements and a 20mm offset for the inner curve, with only a 10mm offset for the outer curve. Since I don’t model in HO, this should not be considered a standard.

Chuck (Modeling Central Japan in September, 1964 - in 1:80 scale, aka HOj)