Abstract: A highly reliable early warning system is disclosed. The warning system provides immediate detection of railway activity and early warning of dangerous railway conditions to train crews and to Rail Traffic Control offices. The warning system has acoustic sensors coupled to one of the rails of a railway for detecting sound or vibration transmitted from physical events. The detected acoustic signals are analyzed by a computer sound recognition system to ascertain the nature of the event causing the signal. If a suspect condition is identified or an unrecognized high energy acoustic signature is detected, an alarm is generated. The alarm signal may be transmitted over any communication system to the Rail Traffic Control office and to the trains traveling toward the suspect track location. The system can also detect railway rolling stock problems such as flat spots on wheels or derailed cars. When desired, the alarm may employ wireless transmissions to stop the trains remotely.