I found this classic photograph from the Union Pacific Railroad at my Link page Fallen Flags.Org, which is located to the right of your computer screen at www.rr-fallenflags.org
The 1960's were a great time in America to see and photograph contemporary diesel railroading. Many of the early "First Generation" diesel locomotives that had originally replaced the remaining steam locomotives a decade or so earlier, were still rolling around in daily service. However..age and mechanical issues were begining to catch up with them, and soon many would be traded to EMD for newer locomotives, or sold to various shortline and industrial railroads.
This early EMD model NW 2 yard switcher locomotive from the 1940's era, was still hard at work for the Union Pacific Railroad by the late 1960's. This photograph which was taken by an unknown photographer, is viewed working at Spokane Washington in May of 1969.