How come NMRA HO fine wheels work on NMRA HO standard track?

Here are the dates:

S-3.2 has a date of January 2006 on the standard:

S-4.1 has a date of January 2006 on the standard: S-4.2 has a date of July 2004 on the standard:

Howard , where would the NMRA committee which is in charge of RP25 code 88 wheelsets fall on that list? Mid-Scale Standards? Special Standards? Mechanical Standards?

RP-25 (wheel contour) seems to be pretty independent of scale.

Good question. I do not have the answer. But drop a message to the mid scale person and see what he has to say.

Howard