I loved the concept of Peter F Hamilton’s Commonwealth saga. People invent wormhole technology. Interstellar colonization is done by opening wormholes directly to alien worlds. Except the tech isn’t cheap or easy. IIRC they described an interstellar generator as made of half a cubic kilometer of intricate machinery. They’re giant machines that can open portals to distant star systems.

Because of the immense expense, they need to make maximum use of these gateways. The generators operate on regular schedules, connecting to different worlds in the human sphere of colonization. And to make maximum use of the gateways…they run trains through them. You travel to a distant star system by buying a train ticket.