Hi Paul,
There are some who use Proto 48. Photo 48 is proper 4'-8.5" scaled down spacing between the rails while regular 0 scale 2 rail and 3 rail uses 5' spacing between the rails. The difference is a little over 1/16". The equipment for Proto 48 won't work on 5' gauge track, and the equipment for 5' gauge won't work on Proto 48 track.
Another thing that might make a difference in appearance is that some people use code .148 heavier mainline rail and others might use code .138 and others might use code .125. I chose mine based on what the prototype used. Most 3 rail track uses taller and wider rails than what is generally offered in 2 rail. I think I've heard it mentioned that Atlas 3 rail track is code .225 compared to their 2 rail track offerings which are code .148. Code .225 would be off the charts heavy rail.
Also, unfortunately my friend Joe Ioele won't be joining the discussion about his completed railroad. He is also looking to get his railroad published.
