There could be two entrypoints for in- or outgoing traffic (public transport or individual traffic going to working places or shopping centers outside of the town). This idea would simplify a lot of things, and if you make a game about trains, you are forced to keep the towns quite small in my opinion.
I'm not sure, but I don't really like to have it that way. There're local commutes, tourist, even students (as in the scheme), so I don't think that way it'll fits in. Unless it's really huge, but I don't want things to go slower. (hint : look at the large ploppable mod lots of SC4. The larger, the slower.)
It may be worth to spent one or two hours in playing the RON-Demo, because the rts-genre seem to be closer to the genre of transportgames than the citybuilding genre. And if you look at simcity5, this game seem to have a lot of problems, although many people you never hear may enjoy it
SC 5 (or SC 2013 to differ it from the community-initiated one) just suffered from the main problems at start of an MMO game : everybody tried to rush in, the server crash. Wait for several months and look, now it's stable. There are several community-made mods even now.
I guess I just not willing to play a transport game with loads of premade ploppable objects like in your example, not sure why.