Abstract: A sequential monitoring system is for an interlocking logic system and a track circuit system including a plurality of track circuits. The sequential monitoring system includes an interface between the interlocking logic system and the track circuit system; and a processor structured to monitor a state of each of the track circuits, validate a sequence of state changes of the track circuits, and interrupt and correct invalid track circuit state indications between the track circuit system and the interlocking logic system. The interface normally passes inputs from the track circuit system to outputs to the interlocking logic system. When an out of sequence event occurs, the processor applies a quarantine to a minimum of three of the track circuits in a quarantined area, thereby inhibiting use of an unoccupied track circuit in the quarantined area.

Abstract: A sequential monitoring system is for an interlocking logic system and a track circuit system including a plurality of track circuits. The sequential monitoring system includes an interface between the interlocking logic system and the track circuit system; and a processor structured to monitor a state of each of the track circuits, validate a sequence of state changes of the track circuits, and interrupt and correct invalid track circuit state indications between the track circuit system and the interlocking logic system. The interface normally passes inputs from the track circuit system to outputs to the interlocking logic system. When an out of sequence event occurs, the processor applies a quarantine to a minimum of three of the track circuits in a quarantined area, thereby inhibiting use of an unoccupied track circuit in the quarantined area.