What where those "Auto Train" loco's used for? My best guess would be a special train of autoracks, but I get the feeling CNW wouldn't be giving loco's specialty paint jobs at this point in its history.
These were the general freight locomotives (most likely had HEP too) once used by the Auto Train, which was subsequently taken over by Amtrak in 1983, and now uses standard Amtrak motive power. I don't know their destination in the photo.