The rail system is referred to as the "L"
because most of its rail lines are elevated above the city streets.
There are 1,888 buses, 130 routes and 10,813 posted bus stops. Average weekday ridership was 873,147 in 2015.
There are 1,492 "L" cars, eight different routes, and 145 train stations. Average weekday ridership was 767,730 in 2015.
The rapid transit system provides transportation to both of Chicago's major airports, O'Hare and Midway.
1892 - The Chicago & South Side Rapid Transit Company, opens and runs 3.5 miles on an elevated track.
November 24, 1936 - Eleven people are killed and 37 are injured when two trains collide at the Granville Avenue station.
October 17, 1943 - The State Street Subway opens.
October 1, 1947 - CTA begins operating, taking over routes formerly serviced by the Chicago Rapid Transit Company and the Chicago Surface Lines.
November 5, 1956 - Two trains crash at the Wilson Avenue station, killing eight, and injuring nearly 200.
June 21, 1958 - Streetcar service ends.
February 4, 1977 - Four train cars swerve off the elevated tracks and fall to the street below. Eleven people are killed and 183 are injured.
September 3, 1984 - The Blue Line begins service to O'Hare International Airport.
February 21, 1993 - The CTA renames all of its rail lines, using colors to identify different routes.
October 31, 1993 - The Orange line opens, with service to Midway International Airport.
August 18, 1997 - Fare cards are first used.
June 1, 1999 - Use of tokens is discontinued.
June 25, 2006 - The Pink Line opens.
February 7, 2010 - Widespread service cuts are implemented to close a budget gap. Layoffs impact nearly 10% of the workforce.
March 24, 2014 - A Blue Line train derails at the O'Hare International Airport station, smashing through a barrier at the end of the tracks and careening up an escalator, injuring more than 30 people. A transit union spokesman tells the Chicago Tribune that driver fatigue likely caused the accident.
July 1, 2015 - The CTA introduces a new payment method called the Ventra fare system, with reloadable cards that are tapped to enter turnstiles.