South Side Elevated Railroad - began operations in 1892. Lines to Jackson Park, Englewood, Normal Park, Union Stockyards, Kenwood.
Lake Street Elevated Railroad - began operations in 1893. One line west from downtown Chicago. In 1904 was renamed the Chicago & Oak Park Elevated Railroad.
Metropolitan West Side Elevated Railroad - began operations in 1895. Garfield Park main line to west side and Westchester, with branches southwest to Douglas Park and northwest to Logan Square and Humboldt Park.
Northwestern Elevated Railroad - began operations in 1900. Main line north to Howard Street, with branch to Ravenswood and extensions to Evanston and Skokie.
The South Side and the Lake Street lines originally used trains powered by steam locomotives, but both lines were converted to electric operation within a few years. All original rapid transit lines were elevated, except for a few outlying segments at street level. Those street level segments would include crossings, complete with gates bells and flashers. All routes used a conventional elevated structure, except for a ballasted embankment north of Lawrence Ave. on the north side. That ballasted embankment carried freight trains originally operated by the Chicago Milwaukee & St. Paul Railway.
Early Elevated Railroad Map
Overview map showing the early elevated railroad companies, and lines operated.
The first subway opened October 17, 1943 underneath State Street, connecting the north side and south side elevated lines.
1914 (from an advertisement in the Chicago Daily News Almanac)
1972 (from a 1972 CTA Route Map)