Incidentally, I just got finished working on a PW whistle tender, and the spark effect when the whistle is triggered is almost exactly what that video shows, but with real sparks! I don't know how much it would damage the track over time, but it would be cool to have a ground circuit like that, but skip the whistle and trigger it in one of the ways you guys are mentioning.
I'll try to get a video this evening, but I suspect any PW guys will know exactly what I'm talking about.