I have a couple of MTH Operating Signal man cars and have been told that it could be possible to retrofit the Mechanism in this car to activate anywhere on the layout with this modification. I have also been told that I would need to get a Lionel Command system for this to work. does anyone know about this.
What you've been told is accurate. I have more than a dozen operating cars, including 3 signalman cars, equipped with ERR Mini Commanders.
To operate the cars via the DCS Remote, you'll need a Lionel TMCC or Legacy command base connected to an MTH TIU with MTH cable #50-1032. You'll also need the associated Cab-1 or Cab-2 to setup each Mini Commander initially.
You can skip the cable if you just want to operate the Mini Commanders using the Cab-1 or Cab-2.