I’m pretty sure this was covered. I am planning a nice simple layout after tearing down the old one. But if anyone may know, what would be the width of a half circle using 36" radius curved HO track. I’m pretty bad in trying to calculate degrees and radius curves. I was thinking 72 inces wide. I could be wrong though. If it’s to large I can go down to 32" as it’s going to be modern with 67’ long cars. Thanks.
Actually it’s closer to 73"->74". The radius measures the centerline of the track, not the outside curve radius.
Don’t forget to allow for the added distance for the easements. The 36" radius would be 72" to center (73" outside rail), but each easement will add an additional inch or so to about 75-76".
And the ‘news’ gets even worse if your room is limited. Besides it being normally a centerline measurement on the radius for track curves, meaning the outer rail and outer tie bits are outside your centerline, you also need overhang clearance for some items…AND…a buffer zone in case something derails to the outside and tumbles off the rails that way. I needn’t be three or four inches, but maybe a solid inch and-a-half with a fence or hedgerow of some kind against which the rolling stock can come to rest without continuing down and onto the Fall of Doom.
What all of us are saying, then, is that the outside diameter of your 36" curve will actually be closer to 73.5", not the 2X36 or 72", but you’ll have to think about that buffer zone. So, add another two inches of flat space if the curve is near an edge of the layout.
-Crandell
From the centerlines, and without easements, a 36" radius curve does form a 72" diameter, producing a half circle as the OP refers to it.
If the concern is for the width of a layout surface, you need a 77" width to safely run trains in case of a derailment where the train falls off the track because the outside measurements of the track take it to 73", plus a 2" overhang on each side.
Rich
Thanks for info, I actually have about 85" of space for the curves to work with so that should work out great! I sort of figured in the extra space in case of derails and I can add a little brush too. Planning on a small storage yard in the center and a few spurs for local loads. [8D]
Well, that is great news.
Rich
That is great news that you have that space; however, are you going to have access to the area within the half-circle, especially to the yard in the center? Openings such as hatches or aisles?
Dante
If you run into a space problem elsewhere, one trick I learned was I use the smallest radius the equipment will run on in places that will not be seen (like in tunnels or behind buildings) and widen it to max I can get elsewhere for better visuals.
Well my plan was to use Sievers benchwork and have the center open. It should be high enough for a duck under, and the side with the small yard use modules that are a little wider at that point and then narrow when going to the main line. Different scenery through the layout so it appears the train travels in different areas. And a few sidings along the way.
I use Sievers and am very pleased with the quality. It is a doughnut plan with a duckunder. I have the 48" legs. By the time I added the adjustable feet, I have about 44" clear. That has been no problem for this 78-year-old body.
Dante
I’m glad you like it. I will buy a few modules at a time and assemble them as I get them. 48" legs would be a perfect and probably will need the feet too. I’m not up there in age yet so it should be no problem for me too. Did you use a cookie cutter setup with elevated subroadbed or just all flat subroadbed? I would like the cookie cutter so I can make elevation changes in the scenery.