TMCC and engine ID numbers

I have swapped countless sound cards between engines for TMCC, they've never failed to work without any reprogramming.  There is nothing user writable on the sound card, the TMCC ID is just in the R2LC.

AFAIK, to this day with the latest Legacy stuff, the sound cards still don't have any TMCC ID or user writable features.  If you swap a tender between locomotives, it'll work on the new one that has a different ID, I do this very often to test function and to isolate a sound issue to either the locomotive or the tender.

Note the term "user writable" used, later sound cards ARE programmed by Lionel, from RailSounds 6 and onward they're a common design for multiple products and they are "flashed" to the correct sound set.

I always assumed values such as Speed Limit and Momentum were stored in the engine. Are they kept in the Legacy base?