I just acquired a new Bachmann Spectrum N scale SD-45, DCC-ready, item # 82761.
I don't want to take it apart to find out which decoder chip goes into it, because I may want to resell it.
How do I find which decoder chip fits my engine (or any other Bachmann engine)?

How do I tell which model I have?
How can I order a power supply for it?

Cool info
Thanks guys

I ordered some Bachmann "roller bearing trucks w/o wheels" off ebay but not sure what to do with them.
I don't see any roller bearings in them.  I know some people order them to upgrade the couplers.
But I got some very nice looking cars that the trucks won't swivel (sposed to but kind of stuck -- and that makes the cars not stay on track going around curves) and I was hoping to use these to not only allow the trucks to swivel properly but also to have minimum rolling friction, like the really long N gauge train (pulled by only one locomotive) that I saw at the World's Greatest Hobby On Tour show in Fort Worth earlier this month.
So I gather that these trucks I bought are maybe only for Bachmann cars (?), but what do I do with them?  Am I supposed to get some wheels that have roller bearings in them?  Or do these tiny plastic trucks have roller bearings hidden in the wheel axle holes?
  I'm confused.