I found this historic 1970's era photograph from the former Chicago & NorthWestern Railroad at my Link page Fallen Flags.Org, which is located to the right of your computer screen at www.rr-fallenflags.org. This is a really cool railfan photo website that I discovered a few years ago.
One of my favorite Chicago railroads that I had grown up with many years ago, was the former Chicago & NorthWestern Railroad. With it's yellow and green color scheme and unique corporate logo on the side of the locomotive cabs, it was a colorful and yet sometimes plain working railroad.
The Chicago & NorthWestern was a big user of switcher type locomotives at the many freight yards and terminals that it owned, as well as on the many industrial branchlines that it had served numerous customers with switching locals picking up and dropping off cars on their spur sidings.
Railfan photographer Dennis Schmidt, photographed Chicago & NorthWestern Railroad EMD SW 1 yard switcher diesel electric locomotive # 616, during a maintenance session at the Proviso Yard locomotive terminal in Maywood Illinois, during late May of 1977.