I read that GTW and SOU had run through agreements from Detroit to Atlanta and/or other places in the south. These trains primary purpose was to get autos and auto parts down there. Did these trains use the DT&I? Did GTW have agreements with other railroads like this? I know in the late 80s and early 90s CNW power was common and BN had run through coal trains to Detroit from out west. However, I don't recall seeing mixed power on those coal trains. Those were almost always BN green.