I was converting old Publisher files, and I found a Chicago transit map I made 10+ years ago for an urban planning class. My idea was to expand the CTA (a.k.a The L) as much as possible. The map follows the design of the Kickmap where the colors of each branch correspond to which tracks through downtown it follows.
The map keeps most of the existing system, but expands it to include express trains on most lines. The big expansions in downtown Chicago include a Madison St. subway (yellow) and a Clark St. subway on the North Side (orange). There is a circle line (Line O) surrounding the edges of downtown (more or less the 312 area code) to connect everything, and a short line between the near north and near south sides to connect to Union Station (Line I).
The new branches follow streets with the highest bus ridership and continue them through the city. For example, the busiest single bus route when I made this was (and I think remains) the 79th St. bus, which is why the B route extends down that street from its trunk line. I tried to make connections across the entire city: North Side, South Side, West Side, without the kinds of biases that usually show up in hypothetical CTA expansion maps.
Finally, there is an express train to connect O'Hare, downtown, and Midway on one line. I had the idea of some kind of secure train where one could go between O'Hare, Union Station, and Midway without leaving TSA security. I'm not sure how that would work, but I'm also not sure how 4-tracking the middle of the Kennedy would either.
This map has about 290 miles of tracks on 27 lines. Is it possible to expand the CTA this much? Sure, with many billions of dollars and a can-do attitude! Let me know what you think.