Mike,
That does make a lot of sense in both statements, so thanks for that.
The C&O streamlined Yellowbelly and the Wabash 2046-style Hudson from 1995 did have RailSounds 2, as well as TMCC LCRU2's inside, and they came before the Geeps.
And I was considering that thought of RS3.0 audio boards myself - Lionel does still have some on their parts site that would do wonders for me just plugging into a RS powered motherboard, like the L3A Mohawk and the Commodore Vanderbilt ones, as I would with an RS4/5 audio board.