Hey Frank...
As fate would have, I was walking across the street to get lunch today and passed a retired "hi-rail" service truck (a pick-up with those funky rims with the offset to correspond to 4'8-1/2" "standard gauge" track).
Truck is an '88 -'98 Chevy 2500 with eight-lug wheels and was wearing Goodyear 8R19.5 radial tires...so 19.5 rubber is alive and well, if you scare-up a set of rims...
