Is it possible to add a pair of PM42 Power Management Modules between the command station Rail A/Rail B outputs and run the resulting output from the PM42's on as many as 8 sets of Rail A/Rail B Wires to 8 isolated power Zones?
These isolated power zones could have their Common Zone (Rail A) Wires running through RX1 transponding receivers connected to an RX4 ribbon cable running to the BDL168 for the purpose of interfacing with the SurroundTraxx Multi-Train Sound System.
If this is possible, it would only require 5-6 of the DS lines on the BDL168 to be used to detect a transponder unit any where in one of 6 distinct Sound Zones.
It sounds like you want to use 2 PM42s to protect 8 different power districts and at the same time have transponding to be able to use the Soundtraxx Surround Sound system which is due out soon.
You can use the 2 PM42s with no problem and have transponding in each of the districts.
We're not familiar with the term "Common Zone Wires" but it sounds like you want to connect several of them together via the BDL168 which you cannot do.
You will have to use one BDL168 zone per PM42 power district which would mean 2 BDL168s.
Unless you have a really big layout we suggest 1 PM42, 1 BDL168 and 2 RX4s, breaking the BDL168 zones into 2 transponding sections for a total of 8.