Most of the photos on this site were extracted from reference images (high-resolution tiffs, 20 to 200 megabytes in size) from the Library of Congress research archive. (To query the database click here.) Many were digitized by LOC contractors using a Sinar studio back. They are adjusted by your webmaster for contrast and color in Photoshop before being downsized and turned into the jpegs you see here.

Workers on the tracks at Union Station in Washington on a winter day circa 1920. View full size. National Photo Company Collection glass negative.
That "lookout tower" is K Tower, the interlocking tower that controls all the switches and signals, as well as all train movements in Washington Terminal. Still going strong after 100 years. I'm sure Terminal Rage applies if you happen to work there.
When I saw this photo I ran over to the Union Station Parking Garage and got these updated shots of the same scene as it is today. The parking garage is a lot higher than the original view, which is today blocked by the H Street Bridge, but you can see that the lookout tower hasn't changed a bit.
[An amazing and excellent photo, Paulo. Thanks so much! Click below to enlarge. More of Paulo's pics here. - Dave]
I enjoyed the "Terminal Rage Company" sign painted on the building by the tracks.