NMRA RP'S...Track Width

[willy6]

I was on NMRA's website looking for an RP concerning centerline to centerline width for HO multiple tracks.Another words if I have a dual track mainline, what is the recommended spacing centerline to centerline between tracks and is it different in a yard or siding? I didn't find an RP on the website, is there one that I may have overlooked?

[maxman]

Is this what you are looking for?

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

 

[WaxonWaxov]

Is this what you are looking for?

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

 

So If I am reading that correctly, Ho scale, all classes, straight track is 2 1/16 inches on centerline for parallel tracks?

 

 

[ndbprr]

Yard tracks need adequate spacing so you reach between tracks to rerail or 0-5-0 uncouple cars.  I use 2 1/2".

[dehusman]

I generally use 2 inches for everything.  If you are running long cars or locomotives and tight curves (less than 24" radius) you might want to consider going wider to 2 1/4 inches so you don't sideswipe anything.

Prototype minimum track spacing is typically 13 ft., that scales to 1.8 inches or 1 13/16 inches.  By going to 2" spacing, you are going to 14.5 ft track centers, going to 2 1/2 in spacing gives you over 18 ft clearance. 

A lot of it depends on your value of access vs. appearance.

Dave H.

 

[tomikawaTT]

If you model a prototype, Google that prototype's track standards or contact that railroad's historical society for the prototype track spacing.

NMRA standards tend to reflect the best practices of the transiton era in the Middle West.  If you are modeling present-day in the Wide Open Spaces, the track separation will be a lot closer to (or possibly beyond) three inches for main tracks.

The opposite extreme was found along New York City's Harlem River, where the Jersey Central freight house (accessed only by car floats) had team tracks on 10' 6" centers.  If a housefly lit on the side ladder of a box car it would be at serious risk if there were cars on the next track over!  The same facility had a 90 foot radius loop around the circular freight transfer building.

Chuck (modeling Central Japan in September, 1964 - with parallel tracks on 50mm centers)

[maxman]

Is this what you are looking for?

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

 

So If I am reading that correctly, Ho scale, all classes, straight track is 2 1/16 inches on centerline for parallel tracks?

 

 

Not exactly.  The number they show as minimum for HO straight track is actually 1-13/16 inch.  That number is under the "tangent" column.  The number you referenced, 2-1/16 inch, is under the M(*) column.  If you scroll down to the bottom of the column, the (M*) has an attached note stating that this is the recommended minimum for easy handling, coupling, etc.

As others said, the actual minimum you use depends on how pudgy/steady your hands are, your prototype (wide open spaces/middle of city), etc.  Some layout articles used to reference the smaller number for yards, stating that gave you more yard space because you could get more tracks in a given width of benchwork.  But then accessibility can suffer.  The best thing to do would be to set up two parallel pieces of flex track, put a cut of baxcars on each, then see how easy it is to get your fingers between them.

I don't think anyone has mentioned this, but sometimes the track components you use will determine the centerline distance for you.  For example, if you take a pair of commercial turnouts and make a crossover, the parallel straight routes will end up being a predetermined distance apart.  If you want smaller than that number, some cutting will be required.  And if you want larger, then you'll need to splice in a piece.  And yes, I know, if you handlay your own turnouts you can have the spacing any number you want.