I'm still trying to decide the best way to get a correct Pennsylvania F3 ABA set for freight operations. I've ordered 3rd Rail's F3A Phase IV units, now I need to find a correct B unit to go with it. While a non-powered B unit would be OK, I'm looking at a powered B since I plan to pull long trains with it. For matching power, I would have to buy 3rd Rail's F3B Phase IV model and replace the shell with one from another manufacturer. I'm looking at the nice Phase IIa shells on either Lionel's or Atlas' models, giving the consists a definite grill-screen-grill look.
My question for the forum is: Since they are all "scale" would another manufacturer's shell fit 3rd Rail's frame? It seems like they should fit with maybe some modifications. I want to get some idea if this is feasible before I order 3rd Rail's B unit. Thanks.
