Chicago CTA

The Loop Track Renewal project is one of our biggest construction projects over the last few years. The project involves renewal of track and rail along the Loop ‘L’ and at two of the busiest junctions on the rail system. The Building a New Chicago program, which is updating infrastructure that’s critical to the city—and includes improvements that will help ensure that CTA continues to serve customers as effectively as possible.


The Chicago “L” (short for “elevated”) is the rapid transit system serving the city of Chicago and some of its surrounding suburbs in the U.S. state of Illinois. It is operated by the Chicago Transit Authority (CTA). It is the fourth-largest rapid transit system in the United States in terms of total route length, at 102.8 miles long, and the second-busiest rail mass transit system in the United States, after the NYC Subway.

Chicago’s “L” provides 24-hour service on some portions of its network, being one of only five rapid transit systems in the United States to do so. The oldest sections of the Chicago “L” started operations in 1892, making it the second-oldest rapid transit system in the Americas, after New York City’s elevated lines.