I want to model the Norfolk Southern F9A/F7B set put having problems finding F9s. Is the any exterior difference in them? The most I can find is a different engine and interior stuff. I want to find one in Southern paint so I can get the design right on the Norfolk Southern. I found one or two but the cost is high, and for some reason I can't bring my self to repaint a 200-300 dollar locomotive. Im not that good yet, but getting there. Im thinking of the Athearn Southern F7 in the blue box. Thanks for the help.