Signalling systems comprise of:
- A simple trigger object that detects approaching objects, and can filter them based on direction of travel, name or description and trigger the signal if required
- The signal objects themselves
- An exit sensor to shut down the signal if required.
I make signalling components in brightly coloured shapes, where each signal is colour coded (also with the control buttons) so it can easily be seen what is a part of what when needed. Components and unstick buttons are shown/hidden via the control panel.
As an example, here is a simple priority junction, with the components hidden:
Here are the parts made visible and labelled:
And the signal control panel:
