The Metropolitan main line was a rapid transit line of the Chicago "L" system from 1895 to 1958. It ran west from downtown to a junction at Marshfield station. At this point the Garfield Park branch continued westward, while the Douglas Park branch turned south, and the Logan Square branch turned north with the Humboldt Park branch branching from it. In addition to serving the Chicago "L", its tracks and those of the Garfield Park branch also carried the Chicago Aurora and Elgin Railroad, an interurban that served Chicago's western suburbs, between 1905 and 1953.