Loose wire cited in MTR meltdown
Company says early investigations indicate a breakage in power line support, but full details will be made public after laboratory tests
Faulty design, defective material or poor workmanship could have caused the five-hour disruption on the MTR's Tseung Kwan O line on Monday, the railway company said yesterday.
Train services were halted on Monday when a power failure was triggered by a 30-metre length of overhead power line that came loose and dangled up to a metre below the ceiling between Yau Tong and Tiu Keng Leng. A Kwun Tong line train bound for Yau Ma Tei on a section of track shared with the Tseung Kwan O line had to stop in a tunnel, while another was halted at Tiu Keng Leng station.
The MTR said its initial investigations found that the overhead cable came loose because the copper wire in the triangular support device holding it broke. It had sent the wire for laboratory tests and expected more details of the cause to be identified in the next two months.
The company ruled out rusting, or external influences such as train design, as factors.
The MTR's chief of engineering operations Tony Lee Kar-yun said the triangular device was only used on the Tseung Kwan O line. There were seven such devices at three locations. Unlike the device that broke, which holds two power lines, the other six hold only one. The company said all were checked after Monday's incident and were found to be in good condition.
"The copper fastening wire is designed to be highly durable. We don't know why it broke," Lee said.
Dr Jacob Kam Chak-pui, the company's operations director, said the system was designed by an Australian company, and if the breakage was found to be its responsibility, the MTR would make a claim under the terms of its contract with the supplier.
Meanwhile, he said the company would enhance the robustness of the support brackets at other locations by adding a second metal wire to each unit, and the overhead lines in the affected section would not be used until the laboratory results had been examined. The company would review its contingency measures, Kam said.
In a Legislative Council meeting yesterday to discuss the incident, Secretary for Transport and Housing Professor Anthony Cheung Bing-leung said the Electrical and Mechanical Services Department was conducting an independent investigation and the results would be made public when they were available.
Lawmakers criticised the MTR for the traffic chaos caused by the disruption. They said the company should have prepared better contingency plans and the government should review the policy under which the railway is the major transport mode in the city. The company should also stop contracting out maintenance services, they said.
In addition they called for service quality to be made a factor influencing the directors' salaries.