Plan B (or "Plan L") ...
With ERR parts, convert your MTH DCS loco to a Legacy loco with a "brain transplant" so that the MTH loco will respond to Legacy control commands from a CAB-1L or CAB-2. I hired GunRunner John to make the switchamaroo, and my converted MTH SW-1500 diesel switcher works great with TMCC.
I didn't want to buy the MTH DCS gear necessary to run just one MTH loco on my Lionel-oriented layout.
Mike Mottler LCCA 12394