Can anyone tell me the “Average” distance between the tracks (center to center) when a prototype railroad has a “double tracked” mainline (or a siding that runs parallel to the main)? Thanks, Kevin
You must have read my mind, I was about to ask this question myself as I am about to start.
From NMRA S-8 Track Centers http://www.nmra.org/standards/s-8.html it would be 2 1/16 inch in HO. This would be an average on curves with 1 13/16 for close straight track.
Everything depends upon the size of equipment you run. For practical purposes, yard tracks should be greater than the tangent (straight track) dimension shown.
I’m sure that someone will give you dirrerent dimensions that they use on their layout, but this is the general range. See the Standard S-8 for more.
I am going with two inches even. But my curves are going to be 38", 40" and 42"
I bought some cheap throw away brass flex track at a swap meet and constructed a sample set of double track curves on a scrap piece of plywood , to test my full length passenger cars. I found I could avoid side swipes with 2" spacing and 38" amd 40" radius curves but below that it would seem very very close. I suggest similar testing if you use long cars.
By the way I did the typical bonehead trick of building a four track girder bridge to scale dimensions (I measured the prototype) only to remember too late that 2" spacing is wider than prototype. Back to the drawing board, as the saying goes.
Dave Nelson
Depends on era, of course.
In the period 1900-1960, the typical spacing between two main tracks, or main track and siding, was 14’, pushed out to as much as 16’ on tight curves to allow for overhangs, and to 16’ to 18’ to clear signal masts between the tracks.
For yard tracks, the common center was 13’, but 12’-6" and 12’ were fairly common. About the absolute minimum was 11’-6".
Today, the trend is toward wider centers in both yards and on main tracks. New main tracks are often built with 25’ to 50’ centers so that maintenance can be done on one track without the requirement for restricted speed or a Form B on the other.
OS
I put this picture in the layout forum a day or two ago. This is the eastside Hudson River line about midway between NYC and Albany. I took this picture because I’m making a simple dogbone layout of river shoreline and wanted to match it. Taking a ruler to the picture I found inside rail center to inside rail center about 1.5 times rail center to rail center of one track. That works out to somewhere between 11.5 and 12 feet track spacing.
http://img.photobucket.com/albums/v718/mhackett/railroad/DCP_2595.jpg
Didn’t post this to dispute anything, just want to show one possibly not-too-representative example where they are pretty close together, apparently. This is closer than recommended model spacing, and in fact I cut away the inside bevel of WS roadbed so it wouldn’t need to extend too far outside the tracks (N-scale).
Mike