Originally Posted by
Velo Vol
Their FB post has a little more info...
Union Pacific 4-8-8-4 "Big Boy" #4021 leads a westbound general manifest out of the west end of the yard in Cheyenne, Wyoming during the late 1950's. The overpass in the background is the Colorado & Southern's main line that terminated in Laurel/Billings, Montana. It remains active under BNSF Railway today.