Automatic Train Stop
英[ˌɔ:təˈmætik trein stɔp]美[ˌɔtəˈmætɪk tren stɑp]
An automatic train stop or ATS is a system on a train that will automatically stop a train if certain situations happened (unresponsive train operator, earthquake, disconnected rail, train running over a stop signal, etc.) to prevent accidents from happening.