The C&NW/SP/UP originally had dedicated E2 sets for 'Cities' service. By the time the E8's were delivered, most 'Cities' trains seem to have mainly UP locomotives. The C&NW E8's were delivered in the '400' paint scheme - They may have been used on 'Cities' trains at times, but I suspect they were purchased with '400' assignments in mind. The C&NW's share of the original E2's did get traded-in/rebuilt for '400' service. There were C&NW passenger cars painted in the 'Cities' paint scheme, and were repainted after 1955 in the '400' scheme.
When the Milwaukee Road took over forwarding the 'Cities' trains between Omaha and Chicago, the Milwaukee purchased ABA sets of E9's in the 'Cities' scheme for the service and painted cars to match the UP cars. Eventually the Milw repainted their passenger engines & cars into the UP scheme.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Recently Kato posted the new E8 diesel 10 car sets. I was looking on the internet for the past few days on the Chicago and Northwestern locomotives. Did the railroad used them to pull the City of Los Angeles in 1954 prior to Milwaukee Road soon after. When did that paint scheme come in before or after 1950 when those diesels were debut? http://www.katousa.com/N/E8/index.html
Amtrak America, 1971-Present.