John,
AFAIK, having a common that encompasses the switches should not affect the DCS signal.
You are correct. On my layout, I have tied all of the Commons from all power supplies: track power, accessory power, switch track power, and even the DC power supplies (-) for lighting, with no ill affects.
Just so I'm sure, I'm powering my track via a Z4000 through a DCS TIU, and want to use a Z1000 14V output to power the DZ1000 switch motors on the Ross switches and use the non-derail feature with isolated track sections. The transformers are in phase. Do I tie the commons at the transformer outlets, or should I tie the Z1000 common to the TIU output ground? I notice that if they are not tied, the track ground doesn't work to activate the non derailing feature. Sorry if this has been covered, but I want to be sure.
Tom
