CHICAGO — Construction crews will descend on the Chicago Transit Authority’s (CTA) Red and Purple Line tracks in the city’s Uptown and Edgewater neighborhoods later this year.

They will be working to remove “nearly all of the century-old embankment structure and walls” between W. Lawrence and W. Ardmore avenues, creating more than one-mile of open space underneath the lines, according to a press release from the CTA.

The $2.1 billion project is the largest capital improvement project in CTA history, according to the project’s website. The work highlighted Thursday is part of phase one, with multiple phases set to take place. Phase one construction is scheduled to run through 2025.