Thanks for all the responses.
4 engines, (Legacy) 1 Lionel NP Light Mikado with excursion tender, 1 Lionel NP Heavy Mikado, 1 Lionel new Lionel Berkshire NP 765 , the last one is Lionel Odyssey Blue Comet (2003). Running TMMC (have a Legacy controller but have not removed it from the box). Single loop bus wiring. Have a continuity tester, what wires or track do I need to test? Will get a picture and post it tomorrow. Thanks again for all your assistance.