What would be a good DCC decoder for the subject engine?
You'll need to remove the board installed from the factory. A Loksound 5 nano will have to be hard wired in. Loksound has a ge sound file, but it's for a 44 tonner. If you order, you have to have the file loaded into the decoder. Digitax has a N scale sdXn147ps. With this you need a pr3 or pr4 to down load a sound file. Digitrax has one for the 45tonner.
TSU-1100 Tsunami2 is what I used. Very tight fit for connection wires.
I had a popular vendor replace the Bachmann decoder (+ install a Keep Alive circuit) in both of my Bachmann GE 45 Ton locomotives (see my other post as things did not go smoothly with this vendor). OK, according to the invoice the vendor used a TCS 1425 M1-KAC silent decoder and a TCS 1454 KA1 Keep Alive Capacitor in each locomotive. One of the GEs runs very smoothly whilst the other so-so (some gear noise or "rattling"). I really wanted each locomotive to be sound equipped, but the vendor gave me an inordinate amount of 'push back' so I had to settle for the silent version. Oh, and gone are the dim, orange headlights...nice bright LEDs now.
Ray