CHICAGO (CBS) -- The CTA would have to acquire and tear down 16 buildings in the Lakeview neighborhood to make way for a $320 million rail bypass that would eliminate a longstanding bottleneck along the Red, Brown, and Purple lines.
The bypass project is part of the $1.7 billion first phase of a planned modernization of the Red and Purple Lines, including complete rebuilds of five North Side "L" stations; and renovations to tracks, support structures, bridges, and viaducts between Lawrence and Byrn Mawr. All of the stations being replaced date back at least 90 years.
The entire Red and Purple Line modernization plan – stretching from Belmont in Chicago to north suburban Wilmette – will cost about $4.7 billion.
To make way for the bypass, the CTA would have to acquire and remove 16 buildings next to the existing tracks, most of them condominiums or apartments three to five stories tall.
The CTA would have to acquire three other buildings for the planned renovations of the Lawrence and Bryn Mawr stations.
Work on the bypass would begin no later than 2017, and would eliminate the need for Red and Purple Line trains and southbound Brown Line trains to stop and wait for northbound Brown Line Trains to cross a four-track junction just north of the Belmont station.
The CTA said that bottleneck sometimes forces up to three Red and Purple Line trains to wait for a single Brown Line train to cross the intersection, which is especially problematic during rush periods when trains end up stopping for signal clearance every three to four minutes.
"This configuration can produce rippling delays to services on all four tracks, delaying over 40 percent of all weekday Red, Purple and Kimball-bound Brown Line trains," the CTA said in a description of the bypass project.
An elevated bypass would carry northbound Brown Line trains over northbound and southbound tracks for the Red and Purple lines and southbound tracks for the Brown Line, before sloping down again parallel to Roscoe Street just east of the Southport station.
Once built, Red and Purple Line trains would no longer have to wait for Brown Line trains traveling through the junction at the same time.
The CTA estimated the project would improve Red and Purple Line speeds by 60 percent at the junction, and increase the number of trains the CTA can run on the Red Line by 30 percent. An additional six to nine trains could run during rush periods.
The project still requires environmental impact studies and public input as part of the process to secure federal funding.
An open house on the bypass project has been scheduled for May 22 at 5:30 p.m. at the Town Hall Police District station at 850 W. Addison St.
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