I purchased a Wm's Class A that needed a traction tire replaced. It came w/ one 3/4" diam. spare tire. I couldn't find any tires anywhere's. Using the one spare tire as a reference. I purchased some 3/4" diam. for Lionel and made a 3/4" pvc jig to cut the wdth down w/a razor.
Brilliant! Any chance you could post a short video of your setup, and the cutting process?