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Sabotage not ruled out: SBS Transit on NEL disruption

Train operator SBS Transit has revealed it is unable to rule out any causes, including sabotage, until investigations are completed on the twin faults that caused an almost 11-hour disruption in services on the North East Line (NEL) on Thursday.

Addressing the media in a press conference on Thursday evening, SBS Transit’s executive vice president for rail Wong Wai Keong said the main fault was caused by two stainless steel wires that were discovered to have snapped at 5am, which provided support to the electrical system powering the NEL trains.

He said that this was the first time such an incident (where the stainless steel wires snapped) had ever happened, adding, in fact, that they were “expected to outlast the system”.

“This is something that we are still investigating, because (the) two cables are actually stainless steel cables, which are supposed to be very strong,” he said. “And we have looked at the failed cables, the condition of the cable was in a good condition. There was no corrosion, there was nothing bad identified at the moment.”

Asked if the operator would rule out sabotage as a possible cause of the incident, the transport operator’s chief executive officer Gan Juay Kiat responded, “We’re going to investigate jointly (with the Land Transport Authority) on this incident… we’re going to complete the investigation itself and see what caused these steel cables to snap, so we will do that.”

Gan also apologised for the inconveniences caused to some 90,000 commuters throughout the morning peak period, as well as through most of the afternoon, as full service was only restored at 4:35pm, almost 11 hours after revenue service was supposed to commence at about 5:45am.

“On behalf of SBS Transit, we would like to apologise to all the commuters who have been greatly inconvenienced by the disruption that we faced this morning,” said Gan, who opened and closed the conference with apologetic statements.

Disruption caused by two main faults



The train operator explained that the lengthy delay on the NEL was caused by the discovery of two main faults — first, snapped overhead cables that disrupted regular power distribution to the trains, and second, the discovery of low electrical insulation later Thursday afternoon.

The first problem involved a pair of stainless steel cables that were built as part of a weighted pulley system that provides tension to cables that power the trains on the NEL, which staff at 5am discovered had snapped.

These were located about 1km from Outram Park station, in the middle of its 2.2km distance to Harbourfront station, said Wong.

“These (the stainless steel wires snapping) resulted in the balance weight (they were supporting) dropping, and it lost tension, so the cabling, the wiring system there also correspondingly fell,” said Wong.

He also pointed out that the cable support arms that should usually be positioned at a right angle to the power cables became misaligned in the process.

Gan added that the resumption of services along the five affected stations — Dhoby Ghaut, Clarke Quay, Chinatown, Outram Park and Harbourfront — was delayed by two hours initially (from noon to 2pm) because “it took longer than expected to repair the overhead cables”, after an initial estimate of about seven hours, after they first discovered the fault.

Wong explained that repairs and replacement of the overhead cables were completed at 1pm, but resumption of services was further pushed back after a second issue was discovered during a series of final checks being run across the affected stations — the electrical insulation level across the power cables was lower than it should be, meaning that if power were to be run through them, the system would be at risk of short-circuiting from a power trip.

For this, a temporary fix had been implemented, said Wong, who added that the affected stretch of cables would be completely replaced when a round of thorough checks and testing is completed at the end of revenue service on Thursday night.

‘Separate incidents’


A separate incident in July 2006, which took place in the same stretch between Outram Park and Harbourfront and caused a seven-and-a-half hour disruption on the NEL, was also highlighted but the operator was quick to add that the two disruptions were completely different.

“That involved the porcelain insulator that holds the overhead wires… the failure modes (between the two incidents) are very different,” said Wong.

He also noted that the cable systems had been built brand-new for the NEL, and originated from France, a system unique to the NEL in Singapore, adding that it was approved by the Land Transport Authority (LTA) by virtue of it being the only fully-underground train service here at the time.

Asked if commuters who were not able to complete their journeys by train would have their fares refunded, the operator responded that based on distance fares, commuters will have paid the distance they travelled on the line up to Dhoby Ghaut, where they would then be able to board a free shuttle bus to their subsequent stations on the NEL.

Representatives from the LTA present at the press conference also stressed the importance of Thursday’s disruption.

“The two incidents are different and separate, and there is no link between the two,” said LTA’s group director for vehicle and transport licensing Colin Lim. “We take both equally seriously, though, and will start our investigations into it today.”

Asked if a penalty will be levied on the train operator for Thursday’s events, Lim said the agency will need to complete its investigations before being able to conclude on any final penalties involved.