One of many railroads that had served the city of Chicago Illinois and parts of the Midwest prior to 1985, was the former Chicago, Minneapolis, Saint Paul & Pacific Railroad, which was known by many fellow railfans and historians as "The Milwaukee Road." (Much simpler to remember.)
With their distinctive orange and black color scheme, this railroad was a favorite amongst many local Chicago area railfans like myself and many others across the nation.
I found this color photograph at my link page Fallen Flags .Org, which is located to the right of your computer screen at www.rr-fallenflags.org
Railfan photographer Keith Rottman, photographed this Milwaukee Road locomotive, at the Bennsenville Yard locomotive terminal near Chicago's O'Hare International Airport in December of 1983. after several years and a number of bankruptcies, the Milwaukee Road was acquired by the Soo Line railroad in 1985. The Soo Line itself was acquired through merger by the Canadian Pacific in 1990.