The game really needs more vehicles. But on the other hand side it forces you to make interesting choices. Should you really buy the locomotive that came go 200 if you don’t have any wagons that can go that fast? And you also need a big and long track, otherwise they will not reach and profit from the high speed.
Maglev trains are only useful when connecting big distances. That’s one of the reasons we don’t have them in europe. And in the game, my tgv doesn’t even reach the 300 in between two cities if I don’t build a special track with no intermediate stops from one corner of the map to the other.