Providing the basic link, from the alternating current supplied by the Commonwealth Edison utility, to the direct current used by Chicago's streetcars and elevated trains.

Converting From AC To DC

Rectifying, or converting alternating current to direct current, was previously a more complicated process. Requiring large rotary converter devices, and buildings large enough to accommodate the rotary converters.


Some substation buildings were owned by the streetcar companies. While other substation buildings were owned by Commonwealth Edison, which provided additional room in the buildings for the needed rotary converters or newer rectifier equipment. Eventually, CTA assumed ownership of the substations which continue to serve the rapid transit lines.

Chicago Railways Substations
Commonwealth Edison Substations Serving Chicago Railways
Chicago City Railway Substations
Commonwealth Edison Substations Serving Chicago City Railway
Commonwealth Edison Substations Serving Calumet & South Chicago Railway
Additional Substations Serving Rapid Transit Only
CTA Substations

As the electric utility serving Chicago, Commonwealth Edison built many substations throughout the city, distributing electricity to the typical consumers. Most Commonwealth Edison substations were never equipped with the rotary converters, and are beyond the scope of this web page.


Many substations continue in use for the CTA rapid transit, or were more recently replaced with new substations nearby. Some old substation buildings remain standing, adapted for other purposes.

Photos are generally organized by present rapid transit lines, which now are the only present users of direct current from these substations.

Loop Area
Brown Line
Red/Brown Combined Line
Red Line/North
Blue Line
Green Line
Pink Line
Surface Lines Only



Links to substation locations, using Google Maps. Satellite views are also available.

In Chicago, odd address numbers are on the south or east sides of the street, and even address numbers are on the north or west sides of the street. Some substations are not actually located along the named street, but might require walking away from the street through an alley or underneath an elevated structure.

Much information on substations is from the annual reports of the Chicago Traction Board of Supervising Engineers, which provides many details covering the continued modernization of Chicago Surface Lines. No such equivalent resource has been found for the Chicago Rapid Transit, so information is less complete for those substations. But because of the commingling of the power distribution between the streetcar lines and elevated lines, and because the rapid transit system continues to exist, information is available for most rapid transit substations. And any further information would be appreciated. Bill Vandervoort