This facility will ultimately connect the Lawrence Avenue/O’Hare corridor on the North and Northwest Side with communities and recreational amenities along the north and south lakefront, using primarily subway along the Lawrence Avenue and North Lakefront segments, sharing the Central Distributor Subway along the Michigan Avenue and Near South Lakefront segments, and utilizing the existing at- or above-grade Metra Electric South Mainline tracks and Blue Island spur south to Blue Island.

From approximately 18th Street south, a key operational characteristic of the corridor is its shared use with the Metra Electric South mainline tracks.  Existing trackage of the Metra/Illinois Central freight/commuter trunk corridor is consolidated to allow for a latererally separated rapid transit corridor of from 2-4 tracks, including stations.  Several existing Metra Electric stations would be closed or converted to CTA rapid transit stations, new rapid transit stations would be added, and Metra Electric trains would no longer serve stations between Roosevelt Road and 79th Street, except for 23rd/McCormick Place and 55th Street Stations (which would become joint Metra/CTA intermodal transfer stations).  One resulting benefit is a hierarchy of local (CTA) and “express” (Metra Electric) operations.

Development of the overall corridor will be in 4 individual segments, each described below:

B1: Wilson Transfer to Wilson (Red Line)
B2: Wilson (Red Line) to 23rd St./McCormick Place East
B3: 23rd St./McCormick Place East to Grand Crossing
B4: Grand Crossing to Blue Island