Mass Transit

I was wondering if the mass transit could be modified to provide railroad access as well to cities? That would be awesome, and it seems to fit. Just a thought, tell me what you think, and if it's possible...

What do you mean exactly by "provide railroad access to cities" in terms of gameplay? Do you expect that 2 cities with railroads get automatically connected with railway (railraod built on map instantly)? Or to be able to move cities instantly between 2 cities (similar to Civ 2 airports)?

Oh sorry, I meant that it would simply add railroad to the square where the city is.
Edit:
This would just be a supplemental feature to its current function.