I’m a fellow modeller based in Victoria (Australia), I started like many in HO scale, with several layouts to varying degrees of completion. My last and largest HO layout was a double track oval with a lot of electronic control.
Now I model in On30, that is O gauge 1/48 scale that runs on HO gauge track. That means it is representing narrow gauge railways. I enjoy the larger rolling stock and some unique locomotives that were used in Narrow Gauge railways. I now also cut my own timber to scale for scratch built buildings.
My electronic control devices are on manufactured printed circuit boards often with Arduino (that is small programable computers) to control what I want them to do. I have been doing this for some years with crossing lights and Searchlight signals build for friends locally.
I have have a range of electronic to make controlling model railways simpler that are available to purchase.
Servos can be used for point motor (or turnout) control, or for controlling semaphore signals. These controlers require no programming, the servo angle or distance of travel is set with trimpots using a screwdriver. The direction can be reversed with a switch. A feature of this controller is that power to the servo is turned off once the correct angle is reached. This removed the noise that some cheap servos can make and saves power. The latest controller is for three position semaphore signals with each position being able to be finely adjusted for the correct position.
Crossing lights can be controled using optical detectors for train detection. Flashing Crossing lights turn on when the train is at some distance away but turn off once the train is clear of the crossing. This requires 4 optical detectors per track. Crossings with multiple tracks can be configured.
Automatic Signalling using optical detectors for train detection is also possible. These can be used to control a block of track, a signal at one end is green and the other red, once the train passes the green signal both signals are red until the block is cleared. As the train approaches the red signal (with the block clear) the far signal will change from green to red and after a short delay the signal in front of the train will turn to green for the train to proceed. This could also be used with the servo controller for semaphore signals.
Solenoid point motors, (or turnout control) can be operated with Capacitor Discharge units with high power switching. The switch to activate the solenoid is low power and can be placed away from the solenoid with only small wires, multiple switches in different locations can be used if required.