I have just finished the basic design of my future layout, using WinRail with Peco´s code 83 track and no. 6 turnouts. I find the spacing between two tracks a little narrow, somewhere between 2" and 2 1/4".
What is a recommendable space?
I recently built my layout with a double track curve with the inner radius of 24 inches. With some trial and error, I found that the outer track worked best at a radius of 26.5 inches in terms of appearance. In other words, a spacing of 2.5 inches.
Anand
Hi Ulrich,
Two-inch centers are fine for straight track in HO scale, and you can even get away with a fraction less. Curves require wider centers, and the sharper the curve the wider the spacing should be. The National Model Railroad Association has a standard, S-8, governing track centers for various degrees of curvature in each scale. You can find it at http://www.nmra.org/standards/sandrp/s-8.html.
So long,
Andy
If you take not the modern lines, the prototype has 14’, and in the yard you find even only 12’.
For a model railroad you need at curves a wider spacing. It depends on your longest car. Therefore I’ve made a clearance calculator for me.
Wolfgang
The spacing of parallel tracks has varied with time and prototype practice. Recent multi-tracking projects have had track laid on 21 foot to 25 foot c/c spacing. In the Northeast, there is a lot of multiple track laid with 14 foot spacing.
In general, 2 inch spacing will work for HO, widening the spacing as necessary on curves to provide clearance. (This is where the varous sectional track systems have problems - the curves come in 2" radius increments.) An easy way to widen the spacing is to use a longer spiral easement on the inner curve - looks good, too.
Chuck (Modeling Central Japan in September, 1964)
My planned layout has 2" spacing between tracks and a minimum of 2 1/4" in curves - with the minimum radius being 24". So I guess it will be ok?
If you go to the NMRA standards referenced by Andy Sperando’s post, 2 1/4" is probably not going to be enough for adequate clearance to run full length passenger cars (if you ever intend to do so). I’m not sure what your governing equipment is. For just 60-70ft cars on 23" radius the standards suggest 2 5/16" centers. I would recommend 2.5" spacing on 24" radius curves.
My advice for those who like to operate at the edge of or beyond recommended practices and standards is to set up a test program - and be prepared for the occasional failure. Full length passenger cars (80-85 scale ft) and similar rolling stock on 24" radius curves is very close to the edge. Set up some parallel curves at 24" and 25.25" radius and see if you have enough clearance. Test combinations of your longer and wider items on both tracks. Make sure you test backing up - rolling stock, especially steam locomotives, seem to cock slightly going in reverse, requiring more clearance than in the forward direction. Wlaters full length passenger cars sometimes have problems just getting around a 24" radius curve without worrying about clearance on parallel tracks.
my thoughts, your choices
Fred W
Fred W - thanks for the hint - I will just do that…
I still have that uneasy feeling that 2 1/4 may not be enough - better to find out before the track is laid and ballasted!
This subject crops up a couple of hundred times a year at least.
As Andy S. has pointed out your parallel track spacing is going to be dependent on your curve radii: if you are using broad radius curves–30" or greater–then you could probably get by with 2"/2¼" spacing; if you are using standard radius curves–24" or greater–then I would increase the separation by 1/8 inch; sharp curves are going to require an additional 1/8 inch.
One of the discussions from a year or more back involved spacing in yards. Because of my 12 inch to the foot fingers I had always settled on a scale 20 NScale feet for my yard spacing; one of the forum member commented that his company had just done some yard remodeling somewhere in the south and their yard spacing was–are you ready for this?–20 feet; that 1.5 inches in NScale–2.75 inches in Horribly Oversized Scale.
I might mention here that I recall reading somewhere where in 1940-41 the Onion Specific adjusted their minimum parallel track spacing through the Wasatch to 16 feet to accomodate the future Big Boys; that’s just a hair short of a 29º radius curves; those Big Boys were designed to negotiate 20º radius curves so even the UP believed in giving things plenty of clearance to avoid future problems. Remember that today’s 89 foot flats are longer than the Big Boy’s boiler which was somewhere in the v icin ity of 75 feet long.