Hot Water posted:
My opinion is; the NMRA has excellent "standards" for 2-Rail O SCALE, and most/many of those recommended standards can also be used by us 3-Rail SCALE modelers. However, that said, one of the biggest problems in the 3-Rail hobby is, neither Lionel nor MTH make any attempt for follow "standards", let alone NMRA "standards"! Only Sunset/3rd Rail/Golden Gate Depot and Atlas tend to follow O SCALE "standards".
As I recall, there has never been really a 3 rail NMRA standard for the very reason you list. Most manufacturers have their own standards in 3 rail.
I agree that the NMRA 2 rail standards gauge is very useful for 3 rail scale O. That and the Kadee coupler height gauge. I'd be lost without that one!