There is a a series of caboose general arrangement drawings at http://crcaboose.railfan.net/drawings.htm, but no Reading ones that I could see. I have found at least 2 of the drawings listing 33" diameter wheels on other cabeese that made it to Conrail.
The site states that Reading caboose drawings were in Railroad Model Craftsman July 1982.
I hope that this gets you started,
Unanderra in oz