"@prrjim, I'm curious; is your friend only running MTH engines with PS3 electronics? If so, there may be no "functional" differences, but "feature-wise" he has a somewhat limited (less than the entire universe) pool of locomotives to run. If your friend is running other 3-rail (non-PS3) MTH engines, Lionel engines, Atlas engines, etc., didn't he have to modify the engine electronics and/or motor to install DCC in those engines?"
Yes my friend has installed DCC Decoders in all of his locomotives. You don't need to change motors or mechanical stuff to use DCC. You only need to install a DCC decoder. When he does that he has full functionality of all DCC functions. His pool of locomotives is any model that has been made.
There are decoders available from NCE, Soundtraxx, Loksound (ESU?), Digitraxx, and QSI that are fully DCC compliant, and available for conversions. All of these decoders work with any of the various DCC control systems.
