The $20.4-million project is intended to fix "slow zones," portions of track that don't allow trains to travel at their maximum speed of 55 mph. Trains often must reduce speeds to 15 to 35 mph on the O'Hare branch of the Blue Line because of poor track condition, officials said in a statement.
Construction that will replace decorated wooden rail ties, tie plates, fasteners and foot walks along the tracks will begin in the spring and continue through the fall of 2014.
"Every effort will be made to minimize impacts to customers, including scheduling work that will impact service to overnight or weekends only," according to the CTA.
The project will be funded by grants from the Illinois Department of Transportation and a federal program for improving transportation infrastructure. Contractor Kiewit Infrastructure Co. beat out competitors for the project with a bid of $20.4 million.
The CTA completed projects in 2007 and 2009 that officials at the time said would remove virtually all slow zones on the Blue Line and prevent future ones from developing. That project, officials said Wednesday, fixed track between the O'Hare and Addison stations, and along a portion of track north of the Division stop to south of the Clinton stop.