Up to 3km of data cables operated by Hong Kong’s rail giant would be replaced this month following a serious system malfunction that led to service disruptions and commuter chaos in August, a source within the company said on Thursday. On August 5, the MTR faced major delays on the Kwun Tong Line because water had infiltrated a network of 28-year-old copper cables, causing corrosion and damage, according to an investigative report submitted to the government. The faulty data links resulted in a signalling problem and triggered a shutdown of operations as a safety measure. The faulty cables are expected to be replaced by fibre optics. Signalling fault forces delays in services on Hong Kong Kwun Tong MTR line According to the report by an executive panel, typhoons and heavy rainfall had exacerbated the problem. The review raised three major suggestions including the replacement of cables to be completed by this month. The source said MTR Corporation had accepted the recommendations, but he did not reveal whether any personnel would be held responsible for the incident. “It was a rare and unforeseen situation,” he said. “The way the cables were laid could have led to water damage, especially when the system was installed so long ago.” He said the incident also exposed a loophole in the automatic detection, which only flagged problems when the cable network broke down completely. If signals were still detected intermittently, the test would not alert operators, he added. “This Kwun Tong section is the last stretch laid with copper cables, as all others have now been replaced by fibre optics [which are waterproof],” he said. Hong Kong lawmakers dismayed as MTR Corp fined HK$2m, not HK$20m, for delay Lawmaker Michael Tien Puk-sun said he believed it would cost about HK$100 million to replace the section of cables, and that the rail company had not done so earlier because of costs concerns. But the source said the change had not been made as it would require an adjustment of the entire signalling system, which was a complicated and high-risk task. Other than using a new cable material, the report also suggested enhancing inspection of the signalling system and comprehensive checks on components. The August disruption took place on the Kwun Tong Line and affected train services for more than 10 hours. The source said the panel agreed that MTR Corp had maintained its top priority of ensuring the safety of passengers throughout the event, and handled the situation according to protocol. Earlier in April, another power failure along the line threw operations in east Kowloon into chaos as trains were halted for more than two hours. Stranded passengers had to walk along tracks in the dark and later queue up with hundreds of people for shuttle buses or other public transport.