@Oman posted:I don't have a dog in the fight, but looking at NMRA recommended practices for O gauge, I don't see any reason to think that 2 rail can be run in the same space as typical 3 rail.
Class H R36.5" 14'
Class I R40" 15' (3.75" in 1/48 scale)
... The majority of 3 railer's can't accommodate O-80. To me comparing 2 rail O gauge to 3 rail is like comparing HO to 3 rail O gauge.
I agree. A New York Central Hudson had a 14-foot rigid wheelbase that (according to your data) requires O-73 for a scale-sized 2-rail model. A 3-rail MTH Premier Hudson is listed for O-42. O gauge (3-rail) is a compromise that allows you to run scale-sized locomotives and passenger cars with simpler wiring than required for 2-rail in a space available to many modelers. The trade-offs are the unrealistic center rail, hi-rail track and larger wheel flanges to avoid derailments, truck-mounted couplers, and other deviations from scale (handrails, steps, movable pilots) to provide the necessary truck pivot angles. It is a simpler proposition and less work to build a 3-rail layout and take advantage of the large choice of 3-rail equipment without having to convert it to 2-rail. As much as I would have preferred to have 2-rail track on my layouts, I did not have space for it and had to accept the compromises with 3-rail. I might have done that even if I had the space for 2-rail. All-in-all, the trade-off was worth it to me, but if I build another layout it will be On30.
MELGAR
