I think that Lionel has it wrong with the minimum radius with some locomotives. I suspect that Legacy ES44AC locomotives and Legacy SD40 can clear O-48 and O-36 track with no issues even though they are listed as O-54. My Legacy SD70 ace and Dash-9s clear my O-36 switches just fine. It seems like the other locomotives should as well.
Keep in mind that I have never seen Lionel use O48 as a minimum requirement on anything. Perhaps because it's a unique fastback size and not tubular.
So if it doesn't clear O36 cleanly then does Lionel auto stamp it with O54? I don't know and really only Lionel can answer that question.