It turns out that, like biological evolution, evolution of machinery is the survival of the "good enough". it's probable that the best gauge for railroads, star

It turns out that, like biological evolution, evolution of machinery is the survival of the "good enough". it's probable that the best gauge for railroads, starting from scratch in 2024, would be wider than current standard gauge, but not by a lot; definitely less than 2x wider. the advantage of interoperability is so large that standard gauge will continue to win for a very long time. There are many advantages to water transport over rail, where water transport is possible. water transport is vastly more efficient. The gauge isn't the reason for that, though; the efficiency is in the same order of magnitude regardless of gauge. Water transport is about one order of magnitude more efficient per mile, iirc. Trains are usually faster and more direct, which is their niche.