One of my background tasks for the last year or two has been building an Automated Level Crossing to go by the halt. There are various designs around, but many are very complicated and often too deep to fit under the baseboard.
This shows the gates on the current prototype – it operation, they all move so that they close either the tracks or the road:
Underneath, it’s a bit more complicated:
Each gate is mechanically connected to a servo using a pair of gear wheels. The servos have small motors that are driven by the electronics in the middle.
The end position of each gate can be independently set using the small push buttons on the electronics board. The speed of movement can also be programmed.
Originally, this used standard servo arms to connect the servos to the gates, but these didn’t move the gates to the exact position reliably.
I spent a while looking for better solutions, then looked at various designs of gear wheels on the internet, found something the right size and then printed them on the 3D printer:
They are a bit rough, but serve the purpose and seem to work well.
Now I’ve got the mechanics right, I need to find some better level crossing gates before adding it to the layout.