Traffic lights on the railway.

These are non prototypical lights to indicate the direction of the track switches. They are red/green LEDs in each lamp head swapping from red to green as the points are switched. My phone camera refused to focus on the lights, but hopefully you an see the effect. Each light post is a brass tube on a 3.5mm jack plug. There is a socket under the base board that the post plugs into for mechanical and electric connection making them easy to remove for repairs and for landscaping later.