Tom, the AR controller still needs to be wired from the main DCC bus and all track feeders inside the AR section(s). Each new BD20 needs to monitor all track current to one of the rails Inside the new signal block. Cut a gap in the rail as desired to create the new signal blocks inside the AR section. Pass the track feeders for the isolated rail of each new signal block through a BD20, and back to, or fed from the output of the existing AR controller. The fact that the DCC signal through the BD20 flips phasing/polarity of track power from the AR controller makes no difference.
DonV
