sorry if this is a topic that is beat to death BUT...I can't find any information on this so here is the question...

I have a locomotive: item number 85059, CSX Nscale D8-40C dcc ready, is the comapatable decoder item #44915 and most importantly will it fit without modification, thanks a bunch for any help.

totally new and a little overwhelmed by the "new" dcc tech...I have purchased a digitrax decoder (DZ123PS) for my new loco but I also want to add sound...do the sound decoders act as a "decoder" as well or do I need to install both? where do I begin with a sound decoder? very overwhelming?  by the way I am not afraid to solder etc. I just don't know where to begin, besides buying the dcc ready loco (which I did)

this is a total newbie question so please be patient. I am just getting back into the hobby after a 20 year Hiatus...boy things have changed.

I have purchased a new Spectrum series D8-40C CSX Loco, I want to add 1 or perhaps 2 more locos to this run...not the line, I am trying to find a Bachmann dummy to add to my powered loco and I can't...where should I be looking...local hobby shops are no help? OR should I just buy a second powered spectrum and run them attached? also I have a cool set of Bachmann plus Pennsylvania passenger cars (they light up) and combine...what Loco would best represent these cars being pulled, I am aiming towards reality rather than "just what I like"

thanks for helping an "old" newbie!