Rain storm during Saturday’s NSL disruption ‘not unusually high’, weatherman says

KENNETH CHENG Today Online 10 Oct 17;

SINGAPORE — While heavy, the rain storm that fell over parts of Singapore on Saturday (Oct 7) — when train services across nearly a quarter of the North-South Line (NSL) were crippled — lasted a “relatively short” time and was not unusually high by historical standards, the weatherman said.

Responding to TODAY’s queries, the Meteorological Service Singapore (MSS) said Bishan received the second-highest rainfall of 42.2mm within a half-hour period that day. Queenstown received heavier rainfall during that period, with 45.6mm of rainfall.

However, in terms of daily total rainfall, Ang Mo Kio registered the highest rainfall of 74.9mm on Saturday.

“While the rain over some parts of the island on Saturday was heavy, it was of relatively short duration and the rainfall recorded was not unusually high if compared to the long-term highest rainfall records for October,” said a spokesperson for the MSS.

Around the same period last year, rainfall was even higher. On Oct 3 last year, for instance, 53.4mm of rain fell over Changi in a 30-minute period, said the MSS.

While the rain over some parts of the island on Saturday (7 Oct) was heavy, it was of relatively short duration and the rainfall recorded was not unusually high if compared to the long-term highest rainfall records for October. Source: Meteorological Service Singapore

On Sunday, the Land Transport Authority (LTA) disclosed that a malfunctioning system of pumps was behind the underground tunnel flooding that began on Saturday evening and stopped services completely along six stops on the 26-station NSL.

The malfunctioning water-pumping system allowed water to overflow from the stormwater sump pit, where rainwater accumulates, into the tunnel through the rail tracks where trains from Bishan zip underground towards Braddell.

As a safety precaution, SMRT was forced to de-activate the trackside power supply, halting services between Ang Mo Kio and Newton stations until Sunday afternoon. This thwarted the journeys of thousands of commuters in one of the worst rail disruptions since 2011.

Engineering experts who spoke to TODAY said they were surprised by the official explanation of the events behind the service disruption.

National University of Singapore transport researcher Lee Der-Horng said it was “unique” that not one pump but a system of pumps had failed to activate, sending water spilling into the tunnel.

“They should (have a back-up system), if they don’t have one. If they had one, then that’s even more unacceptable, which means the first (system) and the back-up system all failed,” added Prof Lee.

He called on the LTA and rail operator SMRT to reveal when the pumps were last activated, noting that the devices could not be infrequently used given how common rain storms were in Singapore.

TODAY has sent queries to the LTA and SMRT on whether a back-up to the water-pumping system was in place, and if its systems had set off warnings before the incident happened. Both the LTA and SMRT have yet to respond to the two questions, as well as others on the number of commuters affected.

The extensive flooding in the tunnel between Bishan and Braddell has also raised questions about the extent of damage to the tracks, related equipment as well as the trains.

Assistant Professor Andrew Ng, a railway signalling, control and communications lecturer with the Singapore Institute of Technology, said the electronic components of trackside equipment contain metal, which corrodes easily when brought into contact with water.

This will shorten the lifespan of those components, including trackside signalling equipment and the bogies of trains — the undercarriage to which a train’s wheels are attached — affecting functionality to a certain extent.

He said the authorities should do another thorough check to ensure the equipment are in “sound” condition. Any components that have been affected significantly would have to be replaced, and others closely monitored for such effects, he added.


Flooding in MRT tunnels: Not enough answers, assurance from the authorities
Today Online 10 Oct 17;

The breakdown of train services along the MRT’s North-South Line over the weekend is still a talking point online. Facebook users want the full picture on how the MRT tunnels could be flooded — with a few offering their own theories — while some urge the public to be more understanding towards the workers dealing with the aftermath. Others talk about their unpleasant experiences of being caught in the fray.

Thanks to all those working round the clock. Must be tiring for staff members from SMRT & SCDF (Singapore Civil Defence Force). They must have made weekend plans to be with their families and friends, but am sure that’s not important because they needed to get the trains running... There are crazy things happening around the world... typhoon, earthquake, floodings, shootings, terrorism etc... this is only a minor disruption whereby there are other alternatives for us to get from Point A to B. Everyone just need to chill and stop being so negative. Just adjust for now. EMMA KRISH

We see how you’re trying to gain sympathy by choosing to focus on the hard work of staff members and engineers in this... And no doubt, they have worked hard. But what about any sort of accountability and genuine admission of fault from the people at the top? STELLA JOSEPHINE

Very often, huge advertisement signboards could be seen at MRT stations showing how SMRT employees are working tirelessly at night to keep the system functioning. First, no one doubts the competence of those workers on the ground, and their efforts should be duly rewarded by the authorities and/or operators. And it is their job. However, those advertisements sometimes appear to be intended to gloss over the failings of the management and the Government. SIVAKUMARAN CHELLAPPA

The questions we must ask the LTA (Land Transport Authority) is: Didn’t it know that torrential rains often happen in our nation? After more than 30 years operating the rail system, didn’t it anticipate frequent torrential rains? Just like the Taiwanese, when they built their train network, they are mindful of the frequent and unpredictable earthquakes, or even Hong Kong, the frequent typhoons that happen there. Even when there were breakdowns in service due to all these natural incidents, they took a shorter time to resume train operations... LTA admitted the flood was caused by a pump malfunction. So there was no regular and conscientious maintenance of the system? Somebody is not doing their job properly and conscientiously. KWAN SIEW KONG

The current upgrading works at Kallang River between Bishan Road and Braddell nearby to increase its drainage capacity could have played a part in the flooding, as the canal water flow could have been temporarily diverted, and the water may have found its way through an alternative route into the MRT tunnel... just my thoughts. MEILIZA AGOES

Horrible. Live in Woodlands, study in the city. Been hit Saturday night, Sunday... Took me more than double the time to get home Satirday night on a nauseating bus ride to Woodlands. Poor aircon ventilation, constant braking by bus driver (sudden, not gradual, which causes the discomfort), and then having to take another bus back to Admiralty... The 30-year-old MRT system has functioned so well in the past years, and SMRT should be maintaining or even improving its reliability. I’m glad we have buses and trains in Singapore offering connectivity. I’m not glad that the backbone of the transport system can have a day-long breakdown due to rain. JIN ZHIYAN KIM

*Comments were first posted on TODAY’s Facebook page and are edited for language and clarity.


Maintenance shortfalls behind water pump failure that caused massive NSL disruption: Report
Today Online 12 Oct 17;

SINGAPORE — Inadequate maintenance is believed to be behind the malfunctioning water-pumping system blamed for last weekend’s North-South Line (NSL) train disruption, Chinese daily Lianhe Zaobao reported on Thursday (Oct 12).

“The pump was not operable during a critical period due to a lack of maintenance,” the report said, citing anonymous sources.

Zaobao added that SMRT staff overseeing equipment maintenance could be transferred out of their posts for failing in their duties.

The newspaper also reported that SMRT’s management was mulling over the staff transfers, although the company did not confirm the matter. The report gave no indication as to how many employees from the transport operator could be affected.

SMRT’s vice-president for corporate communications Patrick Nathan told TODAY that the company does not comment on staff matters, but it was strengthening its building and facilities team in light of the disruption.

TODAY’s queries to SMRT and the Land Transport Authority (LTA) on what caused the malfunction, and when the pumps were last serviced and how often they were maintained, have gone unanswered since the start of this week.

The LTA had earlier disclosed that a malfunctioning water-pumping system was behind the underground tunnel flooding that started on Saturday evening and halted services across six stops on the 26-station NSL.

The faulty system sent water overflowing from the stormwater sump pit, where rainwater accumulates, into the tunnel through the rail tracks where trains from Bishan travel underground towards Braddell.

SMRT was forced to de-activate the trackside power supply as a safety precaution, crippling services from Ang Mo Kio to Newton stations until Sunday afternoon. The disruption affected the journeys of thousands in one of the worst rail trip-ups since 2011.

A spokesperson for SBS Transit, which operates the Downtown Line, told TODAY that it had conducted extensive checks on its water-pumping systems and “have not found any issues”.

Earlier this week, TODAY reported that the downpour over parts of Singapore on Saturday, though heavy, was relatively short and not unusually high by historical standards.

The Meteorological Service Singapore said Bishan received the second-highest rainfall of 42.2mm within a half-hour period that day. During that period, heavier rainfall of 45.6mm beat down on Queenstown.

However, in terms of daily total rainfall, Ang Mo Kio had the highest rainfall on record of 74.9mm.

“While the rain over some parts of the island on Saturday was heavy, it was of relatively short duration and the rainfall recorded was not unusually high if compared to the long-term highest rainfall records for October,” the Meteorological Service Singapore spokesperson added.

No comments:

Post a Comment