Chicago Transit Authority Red and Purple Modernization Program

Modernizing and transforming transit in Chicago

The Chicago Transit Authority (CTA) Red and Purple Modernization (RPM) program consists of flyover bypass bridge structure, the rebuild of four existing stations, two temporary stations, several signal and audio houses and a new signal system that will alleviate congestion and enhance ridership capacity and efficiency. As the largest capital project in CTA history, the modernization of this critical transportation infrastructure will provide faster, more reliable and accessible transportation for Chicagoans and will be a transformative achievement for the city’s transit system as a whole. EXP is part of the design-build team, led by the Walsh-Fluor Joint Venture selected to design and build the RPM Program. EXP has participated in nearly all facets of the project, including leading the design of the flyover structure, design of the new and temporary stations, and design of all support structures that make up Phase I of this project.

Design of a new Red-Purple Bypass for more efficient travel

The bypass at the north end of the Belmont station includes a new ‘flyover’ bridge structure that vertically separates trains that previously crossed at the same elevation, causing congestion and delays during peak hours. This bridge also allows increased train speeds through the intersection – saving time for commuters and implementing more modern tracks. Previously, the northbound-to-westbound Brown Line track crossed four north-south Red-Purple Line tracks at the same grade. EXP led the design for the entirety of the new closed deck flyover structure, which consists of four parallel steel plate girders and reaches a height of 46 feet at its highest point. The entire flyover bridge is 1,850 feet long with a width varying from 130 to 45 feet to take into account the dense surrounding environment. The cross frames are positioned every 12 feet along the entirety of the flyover’s length to establish a cohesive system that allows for tight curvature of the tracks. At the highest point of the flyover, a “straddle bent” supports the structure and tight curvature of the tracks with a minimal footprint of only two columns.

Designing for the moment and for the future

Four Red Line stations will be rebuilt as part of this modernization project. The Lawrence, Argyle, Berwyn and Bryn Mawr stations will be rebuilt to increase accessibility and provide modernized amenities. In the interim, two temporary stations served passengers at Argyle and Bryn Mawr while the new stations and track alignments are being constructed. While only temporary, the stations were intentionally designed to appeal to the community, with playful elements and enhanced accessibility. The bright red geometric shape of the temporary Bryn Mawr station has been recognized for its forward-thinking design, standing out as a beacon amongst the larger surrounding buildings and busy commercial strip. The design of each permanent station involved the input of community members and collaboration between the design team, the CTA and city officials – with each station emphasizing natural lighting and cleaner site lines to enhance safety and aesthetics, while integrating elements relating to each station’s surrounding neighborhood.

Continuing phases

As the RPM project continues, major milestones will include the replacement of 1.9 miles of elevated new tracks, reconstructed bridges and support structures, new signal system installation and the opening of four new ADA accessible stations at Lawrence, Argyle, Berwyn and Bryn Mawr.



Site Planning, Architecture, Interior Design, Signage + Wayfinding, Structural, Civil, Mechanical, Electrical, Plumbing, Fire Protection, Lighting Design, Technology Design



“The Red Line provides critical connection points for Chicagoans. Working alongside our partners, we delivered station designs to reflect a sense of community and characteristics to highlight the longstanding and ongoing commitment to improving Chicago transit.”

Jefrey Jakalski, Senior Vice President, Building + Industrial

AIA Chicago, Lerch Bates People's Choice Award, 2022
AIA Chicago, International Architecture MasterPrize, Transportation category, 2022
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