A westbound Union Pacific train changes crews in front of the depot at Cheyenne, Wyoming, in April 1984. The train is led by an imposing UP DDA40X No. 6935. Delivered by EMD in 1969-71, UP Nos. 6900-6946 were called “Centennial” locomotives in commemoration of the 100th anniversary of the driving of the golden spike at Promontory, Utah, on May 10, 1869.
