Chaos in the Underground: Spontaneous Collapse in a Tightly‐Coupled System

Hong Kong's Mass Transit Railway is demonstrably one of the world's most reliable urban transport systems. However, a disruption to the service which occurred in May 1996 provides a classic example of how a crisis situation can spontaneously emerge from an otherwise highly stable action-structure. This incident, the worst on record in terms of the number of casualties, illustrates how an ordered system, characterized by positive feed-back mechanisms, can induce debilitating disorder. Consistent with Perrow's (1984) description of a ‘normal’ accident, the incident was both unpredictable and, for a time, incomprehensible to the system operator, making an immediate and proactive response somewhat problematic. The various organizational responses which followed the incident range in type from the technological fix to the creation of additional slack and the insertion of circuit-breakers designed to disrupt destructive amplifying feed-back loops.