Well it looks like I am following up myself today, but hopefully others will "join on" later today. Not exactly the heart of the Midwest but centered in Utah, Colorado, and New Mexico was the Denver and Rio Grande Western. This is Lionel's interpretation of a some DRG trains.
First is a made up small train including the Lionel postwar #221 DGC Alco from 1963-64 and including the Lionel (MPC) #9200 Illinois Central boxcar from 1970-71 and a #9077 DRG SP type caboose from 1976-1983 (in catalog) and 1984-1991 (uncatalogued).
Next is the Lionel (MPC) # 8602 2-4-0 locomotive from the "Black River" freight set of 1976-78
Hope everyone has a great week
Best Wishes
Don