Thanks K, I have seen both of those sites. I also was confused about the traces to be cut. I looked at putting magnets and a switch on the rear drive axle but due to the side to side motion wondered if they would make contact all the time. I guess it would depend on the sensitivety of the reed switch.
I remember reading somewhere, not sure where, that putting two magnets on the tender axle would give about the same number of chuffs per revolution as putting 4 on the drive axle, due to the difference in diameters. So, this is what I have tried. As I am not too worried about whether of not the chuffs are exactly timed to the driver rotation this seems to work very well, on the test track anyway.
I am aware that this will probably not give prototypical chuff sounds and timing but am more interested in just having sound. As someone said somewhere, "even bad sound is better than no sound".
Perhaps as more Revolution units come in to use someone with more electrical smarts than me will figure this out and then I can always change mine.
Now, on to installing the Revolution and PB9 in my Connie.
Thanks for the input.