I'm new to this and am building a layout to represent my hometown back in it's glory days.  Its kind of a community history project on a 4 by 8 layout.

We'd like to have an HO L&N FA2/FB2 (to match what was in our town) and would like sound.  Is it necessary to purchase both the FA2 with DCC Sound and the FB2 with DCC Sound?  Or just one?