As I dig a little more into this vintage stuff, I'm learning things (mostly here) I did not know; it's a fascinating field. I purchased a copy of Wills' "American O Scale": wish it was more in depth, but as far as I know, it's the only book about this subject...which makes it also the "best". 
There is lots out there about pre and post war Lionel-type stuff, but very little "scale" info. I think (hope) some of you guys can write up a more complete overview of this (I think) important aspect of the hobby.
On another thread, I had mentioned I got a pair of Auel trucks and that I did not know they were made to 17/64"; so just for kicks, I took this Athearn car (with I'm guessing All Nation trucks):
...took those off and put on the Auels.
Kinda reminds me of something like this: 
Also picked up a pair of Monarch couplers...very nice detail:
...but rather large as compared to MDC or dummy types:
I can only guess that long "stem" was made that way for use on a passenger car...?
Anyway, just wanted to share some observations, in hopes it might trigger some responses.
Hope everyone is staying healthy. 
Mark in Oregon
