[David Johnston2]

Trains IN SPACE. At the front there's a stardrive module that creates artificial wormholes. At the rear there's a propulsion module that pushes the whole thing forward. In between there are cylindrical passenger, cargo and reaction mass modules locked together to turn the whole thing into one long structure that will fit through the wormhole entrances. The passenger modules rotate to simulate gravity for the passengers. Each module has it's own low intensity reaction engine so they can move around a bit independently and link upw with the trains or detach and move into orbit.