Hi Dave:
The LionChief Plus, only works with the LionChief Controller, that is assigned to that locomotive. Think of it as a garage door opener, you would not want to share that radio channel with your neighbor. I also belong to two Radio Controlled Airplane Clubs, we all now fly on one frequency. That is 2,4GHz. the Receiver & Transmitter will find each other and keep them together. Just like a garage door opener.
Legacy, TMCC & DCS are not compatible, with LionChief or LionChief Plus. Lionel is going to be shipping a Universal Remote, this spring that with remember any 3 locomotives that are assigned to the universal remote and can be changed at any time.
I just purchased today my 3rd LionChief Plus Locomotive, Rio Grande FT, A-B-A Units. I like this system because when I have visitors to the train room, they each get a locomotive and a controller. No sharing a Legacy Remote or a DCS Remote. One more thing, if my MTH / TIU / or DCS Controller does not work, I have 19, locomotive that are dead on the tracks. If a LionChief Plus loco goes down, only one engine is dead on the tracks.
Hope this helps, always enjoy talking with you about trains. Gary