Wendel is a good source--you should get a lot of great detail once the museum can open. Also, Nov/Dec '86 Gazette has a Gary Caviglia plan for the car though I can't vouch for its absolute accuracy. Also, May/June '79 Gazette has a plan for boxcar 1011 by Michael Collins. I believe the Demoro or Ferrell books may also have published plans?
Dave Eggleston
Seattle, WA