The interconnected elevated bridge portions of the CTA 'L' could be considered one of the longest bridges in the world, at about 40 miles long. This does not count subway, ground level, or solid embankment portions of the total 102.8 mile CTA. This would be the 7th longest bridge in the world, and 1st longest in the United States. These interconnected portions are the Chicago Loop, the entire length of the Green Line, the Red Line from Leland to Fullerton, the Brown Line from Western to Chicago Loop, the Pink Line from Pulaski to Chicago Loop, and the Orange Line from Canal to Chicago Loop.
All lines are interconnected, allowing rolling stock to be rotated throughout the system. Example in Photo #3.
The Chicago, North Shore & Milwaukee Railroad operated its trains over portions of the CTA until its demise in 1963. Its tracks from Howard Street to Skokie then became the modern CTA Yellow Line.
Includes many notable individual bridges, two of which are moveable bascule bridges, and several which no longer exist. These individual bridges are listed in category "Chicago Transit Authority".
Various proposals for new lines such as Circle Line, and incorporation of Metra Electric Line as Grey Line.