Once upon a time, I experimented a kitbash of a k-line baggage car into a more accurate door of a prr b70. It failed my quality test. But I have admired the PRR theater cars and the interesting end door design and arch roof. In my recent interest in mail trains I found a photo of PRR # 6077 B60a American Railway Express car, blt 4-12-29, with arch roof and 6 wheel trucks and the large end door. Hagley Dig. Archives. However on closer inspection of the photo, it looks dimentionally more like a PRR b70b no diagrams of b60s show 6 wheel trucks!?
Later I found a photo on the net crediting S. Berliner of an end loading b60a #6262 round roof, porthole windows 4 wheel trucks, marked Railway Express Agency.
I don't have the skills to scratch build or kitbash well enough and would not invest $150 in a Weaver or Lionel b60b to try. I will continue to search for a walthers kit just in case I get brave again.