G scale is strange also in that 48" diameter seems to be the standard. This makes the track just slightly to big for a 4 x8 sheet of plywood . I did see 31" G track on Ebay but it is not common. Don
I wouldn't say that the 48" diameter of G is quite the standard, but that is the diameter of track that comes with most all G starter sets. Most folks, once they get really involved in G, go for a larger diameter/radius, and there are plenty to choose from, including flex-track in brass, stainless steel, nickel silver, and aluminum.
I, too, have always thought it a bit strange that they went with 48" as a minimum because it will not quite fit on a standard sheet of 4x8 plywood, but who can explain some of the things that go on in this hobby in any scale?
Hartland Locomotive Works (HLW) offers G track w/built-in roadbed in a 36" diameter--works well enough with short-wheelbase locomotives--and at one time Aristo offered even tighter curve sections (perhaps they still do). My garage G layout uses the 48" and some wider curves. The Marklin track, which I like best, has a 5-foot minimum diameter curve. I have a tone of that track, but no place to use it these days unless I just do a point-to-point pike for my many Marklin MAXI trains.
