Red and Purple Modernization Project

The Red and Purple Modernization (RPM) Project is a multi-phased reconstruction project coordinated by the Chicago Transit Authority (CTA) in the North Side of Chicago, Evanston, and Wilmette. As part of the broader Red Ahead program, the RPM project plans to replace aging infrastructure on the North Side main line north of Belmont station and the Evanston branch. The latter branch is served by the Purple Line, while the former north of Belmont station is served by the Red Line and the Purple Line Express. Both of the Chicago "L" branches were built between 1900 and 1912, with most of the section north of Wilson station being embanked by 1931.

Early planning for the project began in 2009 with a vision study, which assessed the conditions of the two branches. The CTA opted for modernization in 2011. Construction for Phase One of the project occurred from October 2, 2019, to July 20, 2025. At the junction between the North Side main line and the Ravenswood branch (Clark Junction), the Red-Purple Bypass Project replaced a level junction with a flying junction, allowing northbound Brown Line trains to cross above main line tracks. Additionally, Lawrence, Argyle, Berwyn, and Bryn Mawr stations as well as a section of the viaduct hosting these stations were rebuilt.