Bill,
Back in 1989 the Derrick OP had a new roof put on. We(carmen)installed a new deck of Mahogany(someone got a great price on the wood) and Bill Lock, Glendon Castile, and someone else installed canvas and endocrile (?) a tar like substance over the deck. Check out the Friend's Work Session Tape from that work session. I think most of the process was filmed by Ed Walton.
In 1990 only the canvas and endocrile was installed on the 0503 caboose. I know Craig Kumler helped on that job. I'm not sure who else helped out.
Good luck! It sure looked like a messy job.
matt j.