Atlas O72 Switch versions

I have had the same problem purchasing used. I think you are getting 'new old stock' and maybe pretty old? I don't know, but I think the ones with no switch machine screws were early versions and Atlas made some design improvements after having some problems with the earlier ones. I know the rail joiners were improved somewhere in there, as well as the wire jumpers under the switches being upgraded to larger wire. Early versions of O-54 switches were full size and later versions have the removeable 4-1/2" straight section to make them fit in place of a 10" track piece. Something was changed on the O-72's pertaining to size also, I think, but I forget what. As to when this all happened I don't know for sure, but I got the impression it was fairly early on in the development of the 21st century track line?

I do think the changes were made by Atlas and not caused by changing manufacturing plants in Asia. I know the ones I have been able to get from my LHS (last couple of years) are nicer than most of the ones I have gotten used, and more expensive I might add. Also from talking to Atlas when ordering some parts a while back, they should be shipping new ones again pretty soon. Was supposed to happen by year's end, they said.