These O Scale crossing signals are sold as a pair with 4 heads each or with the crossing gates. All are fully operational and the most scale like we know. These work with our control products or may be used as standalone. We offer an Infrared detection pair to allow for actuation from either direction to the crossing and up to 5 tracks (24″ separation between sensors). The LEDs in the cross bucks are dual sided. Additional items are available via special order. You can see more at Crossing Signal Detection and Driver Board.
Note it is easy to burn out the LEDs if you use beyond the voltage recommended, or other than the prescribed controllers.