Work will begin in the fall to reconstruct and modernize the CTA Red and Purple Lines, including more accessible stations and a rail bypass on Chicago's North Side.

The bypass is part of the $2.1 billion dollar Red and Purple Modernization Project. It replaces the old Clark junction that was built in 1907 to connect the Brown, Red and Purple lines.

The CTA Red-Purple Bypass is visibly missing chunks of concrete just months after opening, which the city said is caused by spalling but is safe.

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 ...