Just wired in a Digitrax dcc sound decoder (SDH164D) into my Overland Limited 4-8-4; mounted the speaker in the bottom of the tender, and am now living large.  Learned a lot in the process too. Removed the motor capacitors and resistors as well as the LED and little circuit board, I'm only using the decoder wiring, with 12v 60mA bulbs front and rear.  This is my first foray into HO and it's been a blast.

The Overland Express loco is touchy as can be - it hates 18" curves and barely tolerates the 22" ones.  I like it but it sure needs constant lovin'