The 'L' (sometimes written as "L", El, EL, or L), short for "elevated") is the rapid transit system serving the city of and some of its surrounding suburbs It is operated by the Chicago Transit Authority (CTA). It is the second largest rapid transit system in total track mileage in the United States, after the New York City Subway, and is the third busiest rail mass transit system in the United States, after the New York City Subway and the Washington Metro.
Chicago's 'L' is one of four heavy-rail systems in the United States (the 'L', New York City Subway, PATH, and the PATCO Speedline) that provide 24-hour service on at least some portions. The oldest sections of the 'L' started operations in 1892, making it the second-oldest rapid transit system in the Americas, after Boston. The 'L' has been credited with fostering the growth of Chicago's dense city core that is one of the city's distinguishing features. The 'L' consists of eight rapid transit lines laid out in a spoke-hub distribution paradigm mainly focusing transit towards the Loop. Although the 'L' gained its nickname because large parts of the system are elevated, portions of the network are also in subway tunnels, at grade level, or open cut.
On average 788,415 people ride the 'L' each weekday, 519,959 each Saturday, and 377,308 each Sunday. Annual ridership for 2011 was 221.6 million. In a 2005 poll, Chicago Tribune readers voted it one of the "seven wonders of Chicago," behind the lakefront and Wrigley Fieldbut ahead of Willis Tower (formerly the Sears Tower), the Water Tower, the University of Chicago, and the Museum of Science and Industry.
The first 'L', the Chicago and South Side Rapid Transit Railroad, began revenue service on June 6, 1892, when a small steam locomotive pulling four wooden coaches carrying a total of 27 men and 3 women departed the 39th Street station and arrived at the Congress Street Terminal 14 minutes later, over tracks that are still used by the Green Line. Over the next year service was extended to 63rd Street and Stony Island Avenue, then the Transportation Building of the World's Columbian Exposition in Jackson Park.
In 1893, trains began running on the Lake Street Elevated Railroad and in 1895 on the Metropolitan West Side Elevated, which had lines to Douglas Park, Garfield Park (since replaced), Humboldt Park (since demolished), and Logan Square. The Metropolitan was the United States' first non-exhibition rapid transit system powered by electric traction motors, a technology whose practicality had been demonstrated in 1890 on the "intramural railway" at the World Fair that had been held in Chicago. Two years later the South Side 'L' introduced multiple-unit control, in which the operator can control all the motorized cars in a train, not just the lead unit. Electrification and MU control remain standard features of most of the world's rapid transit systems.
A drawback of early 'L' service was that none of the lines entered the central business district. Instead trains dropped passengers at stub terminals on the periphery due to a state law requiring approval by neighboring property owners for tracks built over public streets, something not easily obtained downtown. This obstacle was overcome by the legendary traction magnate Charles Tyson Yerkes, who went on to play a pivotal role in the development of the London Underground, and who was immortalized by Theodore Dreiser as the ruthless schemer Frank Cowperwood in The Titan (1914) and other novels. Yerkes, who controlled much of the city's streetcar system, obtained the necessary signatures through cash and guile—at one point he secured a franchise to build a mile-long 'L' over Van Buren Street from Wabash Avenue to Halsted Street, extracting the requisite majority from the pliable owners on the western half of the route, then building tracks chiefly over the eastern half, where property owners had opposed him. The Union Loop opened in 1897 and greatly increased the rapid transit system's convenience. Operation on the Yerkes-owned Northwestern Elevated, which built the North Side 'L' lines, began three years later, essentially completing the elevated infrastructure in the urban core although extensions and branches continued to be constructed in outlying areas through the 1920s.
Excerpted from Wikipedia. Click below to read the article.