And sure, a 320km/h 2x8 carriage double deck 4 voltage 3 gauge go anywhere night train *would be great*

But there’s not a hope in hell you’re going to engineer or finance that

A good fleet of a few hundred 200km/h night train carriages that can run on any normal speed standard gauge line and be hauled by different locomotives depending where you run is *good enough* and *can be built right away*