This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
NS lichtseinstelsel wit wit geel . en Threehead searchlightstyle railway signal of the railway signalling system of the Dutch railways Whitewhiteflashing yellow flashes per minute low speed next signal shows red stop at less than braking distance This aspect can only be shown if the previous signal showed whitewhiteyellow low