Passenger Train 6294, electrical fire and collapse of overhead traction line, Mana station, Wellington, 18 April 2008
Status
Closed
Occurrence Date
Report Publication Date
Jurisdiction
NZ
Legacy Inquiry Number
08-103
Electric multiple unit passenger Train 6294 was stationary but attempting to depart from Mana station when an electrical fault on one of the traction motors caused a short circuit and fire in the train’s main electrical equipment case. High current being drawn by the short circuit caused the overhead traction lines to part and fall onto the train.
The train was travelling between Paremata and Mana stations on the North Island Main Trunk, en route from Wellington to Paraparaumu, when the driver experienced problems with the traction motors. The train was a 2-car train set with one motor car and one trailer car and was being driven in the reverse direction from the trailer cab. After passenger exchange at Mana, the driver attempted to depart the platform but the train did not move. Each attempt to move the train resulted in an immediate traction motor overload. The driver was leaving the train to walk along the platform to the rear motor car when there was a brilliant flash above his head. The overhead traction lines parted and the loose ends dropped onto the train and the platform. The electrical equipment cabinet, just below the level of the platform on the motor car, was on fire.
Train 6294 was evacuated and the public were cleared from the area while the potentially live overhead lines were isolated and made safe. There were no injuries and the fire was extinguished before the Fire Service arrived at the scene.
The fault in the traction motor had been developing throughout the previous week, yet weaknesses in the fault-reporting system meant the developing fault went unnoticed, and frequent re-setting of the circuit breaker eventually resulted in it, together with the then-unprotected electrical line contactors, failing.
With no electrical protection between the fault in the traction motor and the power supply, a very high electrical current passed between the overhead traction line and the train’s pantograph, causing the line to melt and part.
(Note this executive summary condenses content to highlight key points to readers and does so in simpler language and with less technical precision than the remainder of the report for the benefit of a non-expert reader. Expert readers should refer to and rely on the body of the full report.)
The train was travelling between Paremata and Mana stations on the North Island Main Trunk, en route from Wellington to Paraparaumu, when the driver experienced problems with the traction motors. The train was a 2-car train set with one motor car and one trailer car and was being driven in the reverse direction from the trailer cab. After passenger exchange at Mana, the driver attempted to depart the platform but the train did not move. Each attempt to move the train resulted in an immediate traction motor overload. The driver was leaving the train to walk along the platform to the rear motor car when there was a brilliant flash above his head. The overhead traction lines parted and the loose ends dropped onto the train and the platform. The electrical equipment cabinet, just below the level of the platform on the motor car, was on fire.
Train 6294 was evacuated and the public were cleared from the area while the potentially live overhead lines were isolated and made safe. There were no injuries and the fire was extinguished before the Fire Service arrived at the scene.
The fault in the traction motor had been developing throughout the previous week, yet weaknesses in the fault-reporting system meant the developing fault went unnoticed, and frequent re-setting of the circuit breaker eventually resulted in it, together with the then-unprotected electrical line contactors, failing.
With no electrical protection between the fault in the traction motor and the power supply, a very high electrical current passed between the overhead traction line and the train’s pantograph, causing the line to melt and part.
(Note this executive summary condenses content to highlight key points to readers and does so in simpler language and with less technical precision than the remainder of the report for the benefit of a non-expert reader. Expert readers should refer to and rely on the body of the full report.)
Location
Mana, Wellington (-41.095314,174.868191) [may be approximate]