A signal set at danger and showing a red light or other stop indication, which a train driver must not pass until it changes or until manually cleared past the signal by a dispatcher.
An indication that a potentially bad or dangerous situation could develop.
The sound or other warning made by a fire alarm.
An electromechanical or electronic bell, klaxon, chime, horn, speaker, strobe light or other device which warns people in a building of a possible fire or other condition requiring evacuation.
An emergency response to a fire by the fire department with manpower and equipment.