"Union Station Waiting Room, Washington, D.C." c.1920 Larger image. "Train Concourse, Union Station, Washington, D.C." c.1910 (postmarked 1912) (click for larger version) Text on back: The Train Concourse of the Union Railway Station at Washington, D.C. is 760 feed in length. There is standing room for 50,000 people within its vast area. At one end...