There are a couple terms that have bothered me for years. Withing the world of 1/4″ scale model railroading there are a number of gauges in use. We have O, On3, On2, On30 and Proto48 in 1/48. Yet some have decided that the term O Scale means two-rail and that O Gauge means three-rail. That seems to be confusing to me. Both two-rail and three-rail O gauge use the same 1.25″ spacing between the rails. So why label one scale and the other gauge. This seems strange to me. Scale is the size (1/48) we work in and gauge is the space between the rail on standard gauge.
I suppose that it isn’t that important in the total spectrum of 1/4″ scale modeling. Proto48 doesn’t suffer this confusion fortunately.