Green is the Lake Street Elevated.
Blue is the pre-1951 Metropolitan Elevated.
Cyan is the 1951 Dearborn Street Subway, which bypassed the old Met and led to the closure of the transfer.
Black is the Loop.
Stub terminals (Market Street for Lake Street, and Wells Street for the Met) are not included.
Source for pre-1951 trackage can be found at the Metropolitan's 1898 map.
Sources:

"The Metropolitan West Side Elevated Railroad". Metropolitan West Side Elevated Railroad. 1898. Retrieved October 23, 2022.
Buck, Thomas (February 18, 1951). "1st Trains Run in New Subway Saturday Night". Chicago Tribune. Vol. 110, no. 7, Part 1. p. 21. Retrieved October 16, 2022 – via Newspapers.com.
Own work
John M Wolfson