[CORRECTION: In our story, we reported based on information that we were given that Alstom was the manufacturer of the power cables on the Circle Line. This is incorrect. Alstom was responsible for laying the cables, not for making them.]
Singapore transport authorities are still trying to determine how a cable that was behind a major disruption in service on the Circle Line Thursday night had gotten damaged.
In a press conference on Friday morning, representatives from transport operator SMRT and the Land Transport Authority (LTA) accounted for the events that led to the service disruption of the entire Circle Line the night before and which had affected 10,500 commuters.
They said a damaged cable caused a power failure at Promenade station, similar to the incident at Dakota that delayed the start of service on the Circle Line in September last year.
The system that powers trains on the Circle Line involves cables that run from a power source to the third rail, which in turn drives the trains in its network.
The cables that connect these power sources to the third rail are conveyed through underground water tanks, and if they are not installed properly, are susceptible to corrosion and damage -- what appears to have happened to one of the eight power cables at Promenade station.
According to SMRT, checks on the underwater power cables were stepped up from every six months to every three months since the conclusion of the Committee of Inquiry hearings earlier this year.
The cable that was found to have had damaged insulation and corrosion, however, had been examined as recently as in the middle of last month without incident, which gives rise to questions as to how corrosion could have occurred on the cable's insulation, exposing it to deterioration from the water it was passed through in the short space of a month.
While SMRT is responsible for checking and maintaining the power cables, the LTA is in charge of replacing them. The cables on the Circle Line were laid by French power generation giant Alstom, with which SMRT's vice president for trains Khoo Hean Siang said the train operator will be working to determine whether the incident could have arisen from a manufacturing fault.
In the meantime, though, SMRT is taking precautions. With this being the same cause that resulted in the Circle Line's second-biggest disruption since last September, the transport operator's president and CEO Desmond Kuek has promised an 18-month overhaul of all the power cables used on the line in order to prevent, as far as possible, another similar incident occurring.
SMRT's head honchos are also mulling the cessation of revenue service for certain stretches of stations during service hours in order to expedite the process, but have yet to decide where and how long these would be implemented.
What they did say, though, was that their focus will be on the six or seven "problematic" stations that include Dakota, Promenade and Macpherson, where the water table is built higher than at the other stations on the line. Cables at these stations will be changed first to prevent, as far as possible, another similar incident occurring.
SMRT engineers found and removed the faulty cable at Promenade station at about 3:45am on Friday, and after running power tests on the line at 4am, testing was successfully completed before the first Circle Line train left for Bartley station at 5:40am.
Kuek asserted, however, that these problems do not in any way compromise commuters' safety.
"While we acknowledge that this problem has caused inconveniences during operations, it bears no impact on the safety of the system," he said. "We would like to assure the public that we are taking all measures to ensure the reliability of the Circle Line."
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