A thought - would it be at all possible to transition surface metro that's in the median of a 4-lane avenue into underground metro while leaving the road on the surface? I know if can probably be done by splitting the 4-lane into 2 oneways and a little anarchy magic, but a cleaner method would be pretty useful to have.
A similar kind of adapter for going to elevated metro would also be neat.
Either way, really looking forward to this mod and hoping it integrates well into existing metro/tram networks.