I guess I assumed that changing the deceleration CVs on the chip would simulate coasting. If decel CV is set to minimal deceleration then the train should coast but will eventually stop without any braking (although unless you have a very large layout it might take more than a few circuits of the 'standard' layout). I tried a friend's RealDrive equipped sound chip in my 079SA and if I recall correctly it stopped from whatever speed it was doing after about 2.5 circuits of a 8x4' layout. Not practical for prototypical stopping to throttle off a scale mile of two down the track and hope to hit the stopping point, I grant you. I supposed that 'braking' temporarily changed the decel CVs setting to slow the loco when F4 is toggled on or off, just like there has to be some change in these settings when 'light engine' is selected. Thanks for your thoughts on the sound chips. Really liked the RealDrive when I ran the loco. Will be investing in these at some point, I think. Sorry if this is drifting off but JT22 did bring the subject up...
EDIT: Thanks, IT, Noticed you typing away at the same time. very interesting. Would be interested in your post at some point when you can