Let's talk about S-gauge/O-scale:
S-gauge track, in 1:48 O-scale, handily works out to be 3ft. 6in. (42 inches). This Gauge of track is/was pretty common the the former British Empire. It has been called the "Cape" gauge or "Colonial" gauge, among other things. It remains the standard gauge in South Africa (hence "Cape"), where they had fast, modern and large 4-8-4's and Garretts running into the 1990's. I believe that India, Australia and NZ all use/used it, in places. (Canada did not, so far as I know, commonly use it, and the pre-US started shooting at the British before the invention of the railroad (they shot back, too; go figure), so the occasional 42-inch line here was not related to the "colonies".)
One of my many want-to-but-never-will projects was to build a mainline-style, freelance N. American RR using nice S-gauge track and loco/car running gear, built to O-scale.
In an early-1960's Model Railroader mag I saw an article about a freelance O-scale/42" gauge layout built using running gear from American Flyer S-gauge locos and cars. Mostly scratchbuilt from wood (very realistic, also), the steamers were dummies with AF diesel power trucks in the tenders.
Really captured my young imagination. Would like to do it. Never will.