Work began on this station in 1913 followed by its opening twelve years later on May 16, 1925. It was built by the Chicago Union Station Company which was formed by the three railroads that would use the station; The PRR, the CB&Q, and the Milwaukee Road. The Chicago and Alton was not part of this corporation became a tenant of the new station upon it's opening. Today, the station is owned by Amtrak and provides service to both Amtrak and Metra. It is the 3rd busiest rail terminal in the US, after Grand Central Terminal and Penn Station, both in NYC.