Also in case it's not obvious, you'll probably end up cutting your existing DCC bus into pieces for each block, and you'll run a new main bus that branches off to run through the detectors at each group and power the cut up pieces of the old bus wires. Terminal blocks with six sets of terminals might come in handy.
Thanks for your thoughts. It helps me think things through.
Well, what I’ve done is kept the buss uninterrupted, but branched off a feed for each detected block, looped it through the BD20 detector and then split the feed into multiple branches to be soldered to each piece of rail within the block. I like to have hardwired connections and not rely on joiners. Same idea though.
As to the turnouts and crossovers, there were no “control points” with occupancy detection, but if a trailing point turnout was unlocked and presumably (but not necessarily) manually lined into reverse position, the first signal up the line would go red as if the block with the switch were occupied and related signals ahead of it would act accordingly (yellow or red over yellow).
Sidings, also only signaled in the direction of traffic only had pot signals, normally dark but going red when triggered by a train entering the siding. What’s interesting, to me, anyway, is that in order for the train to leave the siding, the head end brakeman would walk up to the switch after the last overtaking train cleared, unlock it (triggering the mainline signal red aspect) and then had to wait for five minutes before the pot changed from red to yellow (there were no greens). This was necessary to make sure another train on the main wouldn’t get a sudden red with no warning.
(In actuality, most heading-out switches were spring loaded and it was not necessary to line the switch back to normal after the caboose cleared. I’m still trying to understand how the timing mechanism worked).
Otto
