Originally Posted by Jared
It's doable, London does it (with driver-operated trains too!). In fact, its what they're planning for the current expansion.
Also, I think you need better East-West transit in the southern areas. A Surrey-Richmond or New West-Richmond express bus would greatly speed up commutes for people along those routes.
otherwise, nice job.
True re: London. However, there are two routes where this occurs - on the Circle Line (intermixing with the District, Metropolitan and Hammersmith and City lines, and on the Northern Line where it branches into the City and Charing Cross Branch, and then rejoins.
for the Circle - London Underground will tell you it is a nightmare logistically and the Circle Line is the reason more capacity cannot be added. They're actually thinking of ditching the Circle to increase capacity.
For the Northern, there is discusison of splitting it into two lines (Edgeware to Kennington via Charing Cross, to be called Edgeware Line, and another High Barnett to Morden via City called Northern Line). To do this, considerable expense would be required on new tunnels at the Camben deep-level junctions, and new interchange capacity at Camden Town Station
So yes, it is done, but not ideal.
Re: east-west southern routes - totally agree.