PRR X36 Boxcar
I came across this most curious car today: http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=x36.gif&sel=box&sz=sm&fr=ge
My guess is that it was an experimental (only one was built) lighter weight car, saving roughly 3,000 pounds compared to the similar vintage X35 cars: http://prr.railfan.net/diagrams/PRRdiagrams.html?diag=x35.gif&sel=box&sz=sm&fr=ge
The X36 was also much wider than the X35 inside (9'4" compared to 8'9") presumably because of no (or a thin) wooden liner.
It looks to me to be very much of a precursor to modern car designs but built much earlier than expected. Anyone have further details on this car?