Yet another step forward with the electrics - nearly there now. I've had two bell code dinger units made to enable the layout operator (driver/signalman) at the front to commincate with the fiddle yard operator (hidden at the back) using prototypical bell codes. These units utilise a modified door bell mechanism (to give single dings each time the switch striker is depressed) operated by a battery powered circuit board at each block post and a change-over micro-switch. Only two wires are required to join the two units - perhaps as well as that's all I'd provided in the wiring loom!

Any way, the unit for the main control panel has been installed - except for the externally mounted PP9 battery. I haven't sourced a suitable mounting clip/bracket, yet.

Photos show the dinger cicuit board inside the panel enclosure and the bell and operating switch on the outside of the panel.

Dinger circuit board.

External panel views showing the bell and operating switch. I hope to mount the PP9 battery on the end of the panel, just below the bell.