Decoder Selection for Rivarossi FEF4-8-4

I recently purchased a FEF locomotive. It has the place for the decoder to plug in. I was wondering what type of decoder should go in there. I don’t need one that has alot of functions and all of my other decoders are digitrax. Thanks in advance for the help.

Digitrax DZ123P is what is in mine.

I put a DH140 in my Rivarossi Big Boy. I connected one of the extra light outputs to an orange LED, dropped it in the firebox, and set it to random flicker. It’s a pretty good fire simulation.

Need a little help here,I have an Rivarossi Y6B With a can motor allreday in it (I THINK?)
How do you get to the motor?and do you need to icealate the motor for DCC or Sound systeams?One wire runs to the tender so no problem there,But I can’t figure out how get to the motor?
Thank for any info you can give me!!
JIM