It doesn't seem like the world has much of a standard though, as much as they have a term "standard gauge". I was on a train from China to Mongolia where they

It doesn't seem like the world has much of a standard though, as much as they have a term "standard gauge". I was on a train from China to Mongolia where they lifted each train car, one by one, passengers inside and everything, to change the boogies for a different track gauge so the train could continue. At the France/Spain border my train changed its gauge mechanically on-the-fly. The tech is there, it's probably some stupid patents that prevent the rest of the world from having this efficiency.