Folks,
This back wall business is still happening; the Colorado Railroad Museum built a brick six-stall Restoration Roundhouse in 2000. Just a few years ago, the Colorado Historical Society donated the D&RGW #491, one of the largest class of narrow gauge locomotives that ever ran on the D&RGW. They had to re-build the back wall of one stall for her to fit inside the building!
I hope the new WW&F #11 will fit in the building when she is ready to go inside.
Ted Miles, WW&F and CRRM Member