Being from the Chicago area, I have always had a great love for the following railroads common to the Chicagoland area:
Chicago South Shore and South Bend:
This was a local commuter service that ran from South Bend Indiana to downtown Chicago. This route serviced the far southeast side of Chicago.
Illinois Central (there is no NOISE in Illinois )
In addition to providing passenger and freight service as a Class 1 railroad to Louisiana and Alabama, the IC also ran a local commuter service to various parts of the Chicago area.
and the Rock Island:
This Rock Island was also a Class 1 railroad and went more southwest; providing passenger and freight service from Chicago to as far southwest as Texas and New Mexico. The Rock Island also provided commuter service to Chicago's western and southwestern suburbs.