February 7, 1888 - Lake Street Elevated Railway Company incorporated.

August 24, 1892 - company reorganized as Lake Street Elevated Railroad Company.

November 6, 1893 - service begins between downtown Chicago (Market Street/Madison Street) and California Avenue, using trains powered by steam locomotives

April 29, 1894 - line in service as far west as 52nd Avenue (Laramie Avenue).

September 22, 1895 - new downtown terminal opens at State Street and Lake Street, using trackage which would later become the Loop, shuttle service introduced to serve Market Street terminal.

May 9, 1896 - electric operation introduced.

October 3, 1897 - trains start operating entirely around Loop, Market Street shuttle continues.

April 19, 1899 - service extended west to Austin Avenue, using ground level operation and overhead trolley electrification.

May 14, 1899 - service extended south to Randolph Street and west to one block east of Harlem Avenue, using streetcar trackage on Randolph Street operated by the Suburban Railroad.

May 30, 1899 - special service introduced to Harlem Race Track (near Roosevelt Road), using Suburban Railroad streetcar trackage. Service would continue until 1904, when race track closed. Lake Street Elevated owned trackage over Cuyler Avenue between Randolph Street and Harrison Street, and introduced a streetcar shuttle over Cuyler Avenue in order to hold the franchise for the race track service.

February 1, 1901 - service extended west of Austin Blvd. to Harlem Avenue, using ground level operation paralleling South Blvd. and replacing most service via Randolph Street.

December 21, 1903 - service discontinued on Randolph Street route.

April 22, 1904 - Lake Street Elevated Railroad renamed Chicago & Oak Park Elevated Railway Company.

July 3, 1905 - Cuyler Avenue shuttle service discontinued.

January 10, 1911 - Cuyler Avenue shuttle service reinstated.

July 4, 1912 - Cuyler Avenue shuttle service permanently discontinued.