Peteski,
I believe you are correct: those PRR code equivalents are for Z scale. Based on height only, in N scale, PRR 155 lb rail (8" high) would be Code 50. 115 lb rail (6 5/8") scales out at Code 41; 110 lb rail (6 1/4") scales out to Code 39; 100 lb rail (6") scales out to Code 37; 90 lb (5 5/8") scales out to Code 35; 80 lb (5") becomes Code 31; and 60 lb (4 1/4") becomes Code 26. The NMRA has dimensional tables for Codes 32 and 25 but, to the best of my knowledge, neither of these sizes has been made commercially.
Cheers,
Thanks, that makes sense about Z. Your N scale conversions agree with mine.