As I wrote earlier, I'm taking a trip to Chicago. I'm looking into how to manage myself without renting a car, and with minimal oil use. Of course I'm flying a plane to Chicago, but what I'm looking at is travel while there.
The Wikipedia has useful pages about the mass transit systems of Chicago.
Mass Transit in Chicago: An overview
Metra is a rail system in and around Chicago.
A few weeks ago I took a "car free" trip to Atlanta. Of course I flew on an airplane, and that involved burning some fossil oil fuel. I also ended up driving my car to the airport. But I wanted to, as much as possible, travel around Atlanta without burning oil.