First of all, THANK YOU ALL for your replies! I read them all, and as we are well aware, this is further testament of how knowledgeable our friends in this forum are.
I ran the sequence four more times, and took a picture (once) with my Nikon camera when the ABA was in the same location as when the anomaly had occurred, and nothing happened; i.e., DCS continued to execute the remaining commands in the Playback, including the PFA, SSD, throw several turnouts back to neutral, etc.
As Adriatic suggested (above)
The problem may never happen again.
No way to prove or disprove any theory if the interference is random.
Hopefully, this will be the case.
About four years ago, when I was starting to lay the track and testing, one of the DCS engines that was 'parked' on a spur, took off on its own, full speed, and on to the partially finished main. My wife Judy and a friend were watching, and Judy exclaimed, "There goes Bush!" She was referring to the SD70ACe Union Pacific Cab 4141, which was the engine that had taken off. I shut the power off, and no harm was done.
This early on engine runaway engine experience, in addition to a couple of other occasions when derailments have caused some DCS locos to come alive (though not take off running) further convinced that my decision to be able to turn off siding, spurs, and even main line districts when not in use was a sound one. So I have installed toggles switches at the control panel, and relays close to the tracks, and can shut off any section I want.
Thanks again to all, and if by chance this happens again, I will let you know. (Hope it doesn't happen.)
Alex
