As an addition to the current trains, or maybe a replacement of them, I'd like to propose adding suspended trains to the game.
This system would allow a stackable design, both vertically and horizontally for regular pieces of track to keep trains neatly organized.
belts will attach to the belt in/output on the platform of the station, with storage underneath the station as opposed to on top of it.
trains would not have any actual cars for freight, but instead would have several of the current 'grip parts' that currently get the cargo off/in the freight cars, connected to the locomotive.
At a station, the door in the ground of the station would open up, hydraulic arms would lift up a platform to the freight grippers, until in reach where they snap onto the freight box.