Instead of using text and photos of the spaghetti jungle under the layout, I made a schematic of the "electrics".
How it works
There is no computer input, DCC Accessory decoders or Throttle operation controlling the Signals. Operating the Control Panel Toggle Switches if appropriate, provides a "ground" for a Red and an "open circuit" for a Green, "input" to the Tam Valley Octopus III to operate the Semaphore's Servo.
With "occupancy" detected by the BD20 etc, (current flowing to the loco) of the Block "ahead", the appropriate two GREEN Signals are positioned to RED, shown below.
BOTH Operators have a Green. Who goes FIRST?
Make sure "your" Signal is green before passing it.
I could add some sort of time delayed removal of track power, in this above scenario, to Blocks 1 and 3, to correct a slack Operator not paying attention to his Signals - lots of time and effort. It is much easier to banish a serial offender to make the Coffee.
The above circuitry is repeated 4 times for Blocks 1, 3, 5 and 7, see below, to only provide one train in the Block. Trains are allowed to pass in Blocks Broadmeadow, Blocks 1, 3, 5 and Werris Creek. Home and some more Distant Signals will be added later.
While this above basic signalling method is not "exactly" prototypical of what happened on this section of the Main North in 1965 where hundreds of staff controlled the trains, it provided me what I wanted, bi-directional running, keeping Operators apart on 40 meters of single line and it's automatic. See the below layout video:
If you want to make it more difficult to understand, see my original Blog entry at: http://mainnorth.blogspot.com.au/2017/01/
SCMRA (Southern Cross Model Railway Association) Epping Seminars
These are held in April at the Epping Creative Center here in Sydney, focusing on the railways of NSW with lots of prototype and modelling ideas etc. Each year there is a "theme". Keep an eye out for details in AMRM etc.
This year it was "The Railways of Southern NSW", with the schedule of the Day copied below. In each Seminar, numerous Clinicians talk/demonstrate about a topic, in this case, about the Main South. While my talk was not exactly about the Main South, I showed how to implement Semaphore Signalling in the "South", similar to what I've done on my Main North.
These Days are excellent for NSW modellers of any era. I hope to see you next April.
The Whiteboard had a list of suitable themes for 2019, with the "Main North" having the highest interest (and I only voted once). Fantastic- right up my alley. I will do a Clinic and offer a visit to my Main North layout.
