With metal poles and ladders, these scale signals will look great along your right-of-way. The 3-color lights have a realistic slow changing. The base has optical sensors built-in with a sensitivity adjustment. Just apply power and put them next to the track. These signals do the rest.
When the train is sensed next to the motor moves the signal to the stop condition and shows RED. Four (4) seconds after the train passes, the signal changes to caution showing YELLOW. After three (3) more seconds the signal returns to clear showing GREEN.
They have separate inputs and outputs so they can be daisy chained. The down track signal will hold the up track signal on yellow until the down track signal goes off red.