Amtrak EMD GP7 760, former Frisco 610.
Tom Golden photo.
Amtrak EMD GP7 No. 760 switches a train below Harrison Street Tower on Chicago Union Station trackage as seen from Polk Street in May 1983. This overpass is now gone and the tower is no longer use... (more)
Another Amtrak oddity that could be found at Washington Union Station was the GP7, there were about 16 of these on Amtrak's roster at the time of the photo.