The City of Chicago is undertaking a $492-million, four-year program to overhaul a mass-transit line extending between downtown and Chicago's O'Hare International Airport.
Beginning in mid-2014, the Chicago Transit Authority's (CTA) Blue Line will undergo track and infrastructure improvements, in addition to signal, power and station house upgrades. Rather than complete track replacement, plans call for a series of track improvements along the 12.5-mile line, which consists of subway tunnels, elevated structures and ground-level track along I-90, an expressway linking O'Hare to downtown.