Thanks for your reply Steven.
I'll do some experimenting.
Digitrax told me I had to "Deselect" the address to get the "Shut Down" sound of the diesel engine.  But they didn't tell me how that was accomplished.  Maybe it's a function on their DCC systems?  They also said CV-6 was for non-Digitrax systems ... set to 6 the sound times out after "deselect" ... set to 0 = no time out.  Have tried both numbers without any results.  New & Still learning !

Function 8 seems to lower the volume but not "deselect" the address.  Deselecting would play my digitrax "Engine Shut Down" sound routine ,before stopping all sounds.

Am I missing something, or is deselecting an advanced function ?

Is it possible to deselect an Address with the EZ Command DCC System?
If so ... how it it accomplished.  This would allow my sound module to "Shut Down" the engine.