85' Smooth Sided Passenger Car Questions

[RAM]

I don't know why any locomotive was meant to pull only Budd cars.

[Captain Crutch]

I don't know why any locomotive was meant to pull only Budd cars.

Its not that it's an only pull kinda thing, it's just the loco was shaped in such a fashion that they're meant to look really good with budd cars. The design was short lived so they were only able to pull budd cars before they all were retired. It's the loco in my profile picture. One still exists at the B&O museum. Anyways I'd like to know because walther discontinued almost all the ones what the loco would actually pull. So I need some to go with the loco.