Automatic track warning system

Automatic track warning system (ATWS, German: Rottenwarnanlage) is a technical device used during track construction for occupational safety. It warns the construction site workers of an approaching train. In Germany, it usually consists of a series of signal lights and acoustic warning devices, which are mounted on steel poles or tripods at the edge of the track bed every 30 meters. There are wired and wireless systems that are automatically activated when a train approaches, for example by a wheel contact in the track bed. As long as the ATWS is generating warning signals, the construction site personnel must stay away from the track in question and allow the train to pass. ATWS is considered safer than the non-automated solution, where one worker constantly watches for approaching trains and alerts his colleagues.