Chicago transit riders and north side residents are about to feel the impact of the Red and Purple Modernization (RPM) Project, which is about to commence major construction work in Edgewater and Uptown, the CTA announced on Tuesday.

On May 16, crews will begin a more than three-year-long process to rebuild 100-year-old track structures and replace four of the Red Line's oldest stops with ADA-compliant stations featuring elevators, escalators, wider platforms, and other improvements.

The Lawrence to Bryn Mawr Modernization Project will be divided into two phases. Phase A, which starts next month and is expected to wrap up in 2022, will close and demolish the Red Line stations at Lawrence, Argyle, Berwyn, and Bryn Mawr. 

The CTA will operate temporary stations at Argyle and Bryn Mawr, but the Lawrence and Berwyn stops will remain closed for more than three years. During this time, crews from CTA contractor Walsh-Fluor will demolish and rebuild the eastern set of tracks.

Using overhead cranes, crews will install prefabricated track support segments that are built off-site. According to the CTA, more than 1,500 of these segments—weighing a combined 66,865 tons—will be used between Lawrence and Bryn Mawr.

More than 1,500 of these segments will be needed to build the new track structure between Lawrence and Bryn Mawr.CTA

Phase B of the project is slated for late 2022 to 2024 and includes rebuilding the western portion of tracks as well as constructing the four new permanent stations at Lawrence, Argyle, Berwyn, and Bryn Mawr.

Red and Purple Line service will continue throughout construction, but with trains running on two tracks instead of the usual four. Transit riders "should allow extra travel time," the CTA advised on Tuesday.

The $2.1 billion RPM project is the most expensive capital improvement project in the history of the Chicago Transit Authority. It also includes the Belmont Flyover, which will eliminate a congested bottleneck where the Purple, Brown, and Red lines intersect. The flyover is already under construction in Lakeview and is expected to be completed later this year.

Other components of the RPM project include a new signal system between Howard and Belmont. The CTA will also replace Red and Purple Line track structures between Belmont and Newport/Cornelia and expects to complete that work by the end of 2024.

Financing for the project relies on $1.1 billion in federal money and transit-specific tax increment financing (TIF) districts. Future phases of the RPM project have not yet been announced and are currently awaiting funding, according to the CTA.