CNW SD40 879 is joined by SD40-2 6885, a pair of SD18s and a GP7 at Itasca Yard on Superior, Wisconsin's east end. This was CNW's northern most terminal (outside of upper Michigan) and a major connection with Canadian National via the Duluth, Winnipeg & Pacific. During this period it was common to operate 6 trains a day, a pair to/from the Twin Cities, and 2 pairs to/from Chicago.
The EMD SD (special duty) series are a strong and reliable kind of locomotive which still serve America's rails today. They have proved themselves reliable by clocking in several million miles of freight service over several decades.