Chicago Union Station is a major railroad station that opened in 1925 in Chicago, Illinois, replacing an earlier station built in 1881. It is the only remaining intercity rail terminal in Chicago, as well as being the city's primary terminal for commuter trains. The station stands on the west side of the Chicago River between West Adams Street and West Jackson Boulevard, just outside the Chicago Loop. Including approach and storage tracks, it is about nine and a half city blocks in size. Its facilities are mostly underground, buried beneath streets and skyscrapers.Chicago Union Station is the third-busiest rail terminal in the United States, after Grand Central Terminal and Penn Station in New York City. It is Amtrak's overall fourth-busiest station. It handles approximately 120,000 passengers on an average weekday and is one of Chicago’s most iconic structures, reflecting the city’s strong architectural heritage and historic achievements. Its combination of Bedford limestone Beaux-Arts facades, massive Corinthian columns, sparkling marble floors, and magnificent Great Hall, all highlighted by brass lamps, create an environment that captures the imagination of passengers and visitors who enter its premises. In addition to standing out architecturally, Union Station has features that reflect its commitment to sustainability. In 2011, its lighting system was replaced with more energy-efficient light bulbs and motion sensors, reducing the station’s carbon footprint by 4 million tons annually.
