Well, if you want to spend the bucks, you can get a RailSounds 6 board from the LionMaster Legacy T1 Duplex, and it has the same cab number, listed at $100. This is the board I used for my testing of TMCC with Legacy sound boards, so I know it works with TMCC, just no quilling whistle.
Remember, the T1 Duplex is an articulated locomotive, so the chuffs are quite different than the Berkshire, something to consider.
If you wait for the 1/2 off parts sale later this year, you can get this for $50.