FWIW 8" is around 0.092" in HO, so code 100 is about 9% oversize in height.. In O, code 172 is about 3% over (for 48:1) or under (for 45:1), so perhaps you should consider a different scale. ;>)"
Jack, So you are asking me to consider changing scales because my PRR Mainline will likely be laid with track that is not quite but close to 7/8" of a scale inch too tall? Nope, won't do it, "I'd rather fight than switch..." 3^)