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SCMP Reporter

Human error caused delays to more than 18,000 commuters for more than three hours on December 8, an MTR  investigation has found.
An overhead power cable was damaged, causing train services between Yau Tong  and Tiu Keng Leng  stations on the Kwun Tong line  to be suspended until 11.10pm.
Jacob Kam Chak-pui,  head of operations engineering, said each train drew electricity from four overhead cables supported by a manually operated device known as an 'isolator'. The device, which is always locked in a 'closed' state, regulates electrical power among the cables.
But the investigation found that on the night of the incident, the isolator  was in an 'open' state.
The misplacement caused damage to one of the power cables which triggered the direct current circuit breaker, another power control device, to cut electricity  to trains.
Mr Kam said such incidents were rare and staff negligence was to blame. The error had gone unnoticed for one month  after the last  inspection on November 10.
'This has never happened before throughout the 30 years of operation [of the MTR],' Mr Kam said. 'We have [subsequently] checked all the other isolators and found that they are in the proper order. But even if they are left 'open', the safety and normal operation of train service would not be affected.'
He said the system was designed  so trains would immediately stop if damage was detected. He added that improvements would be implemented,  including strengthening  training, stepping up inspections and putting up notices to remind staff to keep the isolator in a closed position.
Acting head of operations Choi Tak-tsan said more than 18,000 commuters had been affected.
'We mobilised 40 shuttle buses which ran 156 trips to disperse over 8,000 passengers,' he said. 'We estimated that about 10,000 passengers had their trips delayed.'
At 7.23pm on December 8, three trains  on the Kwun Tong line, two loaded with passengers, came to a halt between Yau Tong and Lam Tin.
The MTR issued a 'red alert' at 7.30pm, a signal to indicate that a serious disruption has continued or is expected to continue for more than 20 minutes. Power resumed 10 minutes after it was cut, and the first two trains left,  leaving the third stranded at Yau Tong station. About 300 passengers were stuck on the train until 7.57pm when arrangements were made for them to disembark.
The vacated train started to move four minutes later, but was   halted by another power failure. About 18 minutes later, a maintenance crew discovered that a  power cable was damaged 10 metres from Yau Tong station. The MTR issued another red alert  informing the public that Kwun Tong line services between Kwun Tong and Tiu Keng Leng stations would be suspended, and the emergency shuttle bus  was activated.
How the problem developed
7.23pm Power supply between Tiu Keng Leng and Lam Tin stations is interrupted, affecting three trains between Yau Tong and Lam Tin - T35, T02 and T03
7.30pm MTR Corp issues red alert indicating serious interruption to services has occurred or is expected in next 20 minutes
7.33pm Power supply resumes. T35 and T02 depart, but T03 is unable to draw power
7.57pm About 300 passengers leave T03 at Yau Tong station
8.01pm Power is reconnected and T03 leaves, but power is cut off again
8.19pm Staff find an overhead power cable has split 10 metres from Yau Tong station
8.30pm MTR Corp issues red alert saying services from Yau Tong to Tiu Keng Leng are suspended
11.10pm Normal services resume
Source: MTRC



Human error to blame for electrical fault that delayed commuters for 3 hours, says MTR