Rolling stock performance typically follows a ‘bathtub curve’ throughout a vehicle’s ~40-year lifecycle. This is characterised by higher rates of failures in the early stages due to design or assembly defects or staff unfamiliar with the equipment, which falls to a lower, relatively stable rate of failures during the normal operating period. We would then expect failure rates to increase again towards mid-life or end of life.
The study analyses rolling stock failure rates of individual vehicles within a metro fleet relative to their time in service, allowing members to compare the bathtub curve for new fleet failures across metros and within fleets.
