I did some research, for D&RGW narrow gauge track, the correct sca;e rail is code 140... Basically the same thing Atlas uses for their O gauge track, which is code 148. Meaning, of course, that it is available. I was going to buy a couple of pieces one time, but the local hobby store was out, and cut some ties and scratch some track to see how well it would work with AMS wheelsets, but I never got around to it.
It seems like it would be quite delicate for outdoor use, a derailment of one of the large 1:20.3 locos could easily damage the rail. Stepping on it would be out of the question! But for an indoors layout... I suppose with a little "imaginerring" that even Atlas O Scale switches could be stripped off of their plastic ties and used?