Chicago’s first elevated train began operation on June 6, 1892. Chicago & South Side Rapid Transit Railroad operated nearly 50 steam engines on an elevated track from a station at Congress Pkwy. and Wabash Ave. going south to the terminus at State St. and 39th St. (Pershing Rd.). By the following year, the line extended to Jackson Park for the World’s Columbian Exposition. Part of this line has been incorporated into the current Green Line.
CAF Member Magazine; "125 Years of the L"; by Patrick Miner; Chicago: Chicago Architecture Foundation; Summer 2017, p.6–7
Chicago Transit: An Illustrated History; by David M. Young; DeKalb IL: Northern Illinois University Press, 1998, p. 21, 55, 57.