Waiting for a new 2-wire Lockon, as my original TMCC Powermaster setup used the 6-22914 Powerhouse which has a connection for only a single wire from the PM to the track.
I also was momentarily flummoxed by the connection instructions for the Legacy base. None of the diagrams in the Legacy Control System manual actually show a combination Legacy PM and Legacy base connected together to the track.
I finally found a single line on page 10 of the Legacy PM manual (Step 1 of "Assigning a unique ENG or TR ID#...") that mentioned how to connect them together. I wonder if Lionel should make their manuals a little more explicit in this regard for those of us who only have a graduate engineering degree! 🤣