I have Thomas stuff running on a separate loop from DCC.  The DCC loop powered by the Backmann transformer also has switches powered by a non-DCC transformer.  I bought James from the Thomas seried, based on the hobby store guy telling me that it would run on DCC, under number 10.  When I ran on DCC James gave off a sort of hissing sound.  When I put it onto the Thomas track there was no sound.  I flip-flopped the DCC engine a couple of times trying to see if having it on the track at the same time made a difference but it did not.  As I was putting James away I got a whiff of what smelled like a burning odor.  Does anyone know if there is something you need to do special when using the Thomas engines on DCC?  Or maybe doing that is a bad idea altogether?  I am hoping no damage was done.

Here is the diesel dilemma.  The chassis of a DCC engine has no provision for sound add-in.  The DCC card is proprietary and the chassis take up every mm of space.  I had my sound added to a GP40 by a hobby store owner and the sound works fine it was somewhat deadened by the complete enclosure.  What Bachmann should do is create a speaker spot.  Example:eliminate the metal weight used in the fuel box on the bottom of the train an allow that space for a speaker.  The fuel box could have had a couple sound holes in it for easy sound escape.  If the area is big enough maybe the sound decoder could fit there also.  The proprietary DCC card needs generic coupling jacks so that any DCC Bachmann engine is a potential sound engine.  Right now if you want a particular engine with sound it is wait and see.   Bottom line - your hobby store owner can probably help you get sound on the engines you want.