[Piskvorrr]

Um, nope. The choice of railroad gauge was a historical artifact: in the beginning, everyone had a different gauge, then we had like 15 gauge standards and "standards", and one of them eventually prevailed (through British administrative fiat). The choice was not due to an inherent superiority of this particular gauge, but due to a campaign by George Stephenson. From there, it was mostly network effect: popularity breeds popularity.

Gauge is, most of all, a tradeoff between construction costs (tunnels, bridges, cuttings, oh my! Every additional inch of the gauge gets real expensive in Actual Terrain; ditto for train stations: narrow gauge can fit many more tracks next to each other), and between operating costs (wider gauge cars can be wider _and_ higher, as they're inherently more stable; thus, more cargo on same number of cars).

( ObXkcd: https://xkcd.com/927/ )