A power failure on the Tseung Kwan O line halted MTR services for nearly five hours yesterday, plunging the city's transport network into chaos. A Yau Ma Tei-bound train broke down in a tunnel at 12.40pm, forcing about 150 passengers to walk on the track to Yau Tong station. Trains were affected on the whole Tseung Kwan O Line and between Tiu Keng Leng and Lam Tin on the Kwun Tong Line. The train slowed down after an explosion … then there were two more explosions PASSENGER SKY CHAN Cross-harbour services were also halted for more than an hour in what was the worst disruption on the line in a decade. Six MTR stations were forced to close, leaving thousands of passengers in limbo and causing a rush to bus stations, which were quickly jammed. Commuters were angered by the failure of the MTR Corp's contingency plans. Services did not resume until 5.35pm. An inspection found that a 30-metre section of an overhead power line had come loose and dangled as low as one metre from the tunnel ceiling between Yau Tong and Tiu Keng Leng stations. Lo Chi-ho, divisional commander of Kowloon East's Fire Services Department, said: "We suspect a train was travelling in this section of the tunnel and was in contact with the overhead power cable, causing a power failure." He said inspectors found damage to a section of the cable and the top of the train. The Transport and Housing Bureau demanded that the MTR Corp submits a report on the incident within three working days. Watch: Passengers walk through the tunnel on the MTR's Tseung Kwan O Line Transport secretary Anthony Cheung Bing-leung said: "We will take this into account in the fare adjustment mechanism under which a penalty system also applies." Under the system, the MTR Corp will be fined up to HK$7.5 million for service disruptions lasting about five hours. Adi Lau Tin-shing, deputy director (operating) of the MTR Corp, apologised for the disruption, but refused to say whether the design of the mainland-made train had anything to do with it. "It is too early to draw any conclusion before a detailed investigation is carried out," he said. Lau said the section of cable concerned had its annual check in October. He also denied there were any explosions, as some passengers claimed, saying this was just the loud noise caused when the train protection system was triggered on trains heading for Yau Tong station. One passenger, Sky Chan, said: "The train slowed down after an explosion. It stopped, and then there were two more explosions." Another commuter also said he heard an explosion minutes after the train left Tiu Keng Leng station. Po Lam, Hang Hau, Tseung Kwan O, Lohas Park, Tiu Keng Leng and Yau Tong stations were closed with signs saying: "This station will be closed because of a serious incident. Please leave immediately." At 2pm, cross-harbour services resumed by using a disused tunnel between Lam Tin and Quarry Bay. New People's Party lawmaker Michael Tien Puk-sun, a former chairman of the Kowloon-Canton Railway, said the MTR Corp's failure to repair the system before the evening peak hour deserved an explanation at the next meeting of Legco's railway subcommittee on January 3. Another device on another train on the Kwun Tong line heading to Yau Tong was also grounded after running into a similar problem. Lau Ting Sing, MTR's deputy director of operation, said the activation caused loud noises that passengers described as "explosions." Lau said the company would investigate the cause of incident after train service ends tonight, but added that the cables were usually inspected once a year and the last inspection was October. One of the passengers, Sky Chan, said: “The train slowed down after an ‘explosion’. It stopped then, followed by another two sounds of explosion.” The train arriving from the Tseung Kwan O station stopped in the tunnel about 20 metres away from the platform at Yau Tong station. Passengers onboard had to alight from the train and walk to the platform. One fireman said more than 100 were evacuated from the train. “This station will be closed because of a serious incident. Please leave immediately” was displayed on the sign in the Yau Tong station.