[Braddell MRT]One switch spoilt = change the entire pump system ... KBW must justify use of state funds!!!
What was the basis of the LTA urgent decision ("late by a few days") to change the pumps made on 29Sept given to the fact that it was just the pump activation switch (nothing wrong with any pump functioning) that was at fault? (Separate water level monitor and reporting system also spoilt).
Were the pumps originally damaged due to the quantity of debris collected and uncleared over many years: such that new pumps would have shortened life due to debris build up. Was the pump switch failure due to debris build up too?
What was the debris clearing protocol and was it strictly adhered to since debris build up is a main cause of RECURRENT switch and pump failure: even if a brand new pump system were installed. It is likely that debris since construction was never cleared since it is proven that the 5000cu m sump reservoir was almost full on 7October.
For how long were the water level sensors defective or were SMRT staff ill aware of their existence to begin with.
Who did LTA discuss with wrt decision to replace the pumps? Had a tender for such an expensive replacement work even been called or was it just an in-principle agreement between some LTA director and seductively dressed vendors that some older water pump models need to be changed?
Is the switch an ordinary OEM item, just like the water level detectors that NEA uses to detect high drain water levels: if so, would just a proper schedule of pump maintenance and reservoir sludge clearance be sufficient with replacement of the damaged switch (and a rewiring of switches since the pump triggering designed was ill planned in the current case) (one can only know if something really needs replacement if u actually perform maintenance work on it).
Not all pumps are triggered at the same time due to their stepwise triggering design based upon amount of water collected: thus the pump last to be triggered is likely to be BRAND NEW since even the heavy downpour on 7th October was only 13% of the sump reservoir volume: besides during installation test, the last (3rd) to be triggered pump may be totally brand new (presuming that this is the first instance that the principal trigger switch has ever encountered a fault). The replacement of just the most used (of the three 85 L/sec pumps) would thus suffice (rotating lesser/ unused pumps to more frequent use positions) provided it is proven that replacement is cheaper than parts replacement / routine maintenance.... so what is the LTA's awareness and assessment wrt to the functional state of the pumps since ostensibly, neither LTA nor SMRT were aware of the functionality of the water level meter device, nor the functionality of the pump triggering switch.
Whilst the LTA might have been aware about the need for water removal pumps to be periodically maintained (/replaced if too costly to fix), it seems CONTRADICTORY for LTA to both plan an urgent, entire pump system replacement (suggestive of beyond salvage pump system) as well as blame SMRT for poor performance when provided with beyond repair pump system since i believe that these industrial standard pump systems costs millions of dollars (not a $2 Diaso ornament/ product that many buy on impulse /fancy) and require regular monitoring, maintenance and some spare part replacement over the working life (like escalators and lifts).
LTA needs to be hands on and aware about the functionality of its hardware properties such as the serviceability of expensive infrastructure such as heavy duty water pumps and should operate a routine with contractors like SMRT on the maintenance and periodic inspection of such public infrastructure.
LTA is GUILTY of arm chair leadership and bureaucracy if it's decision to replace the pumps cannot be logically substantiated in the most environmentally friendly and economic way possible. By extension, LTA would be GUILTY of mismanagement of state funds if LTA just threw $$$ blindly at a problem, replacing a probably BRAND NEW pump when the original purpose of having 3 strong pumps with various water level trigger points must surely be for the economical replacement vz downwards pump rotation so that each replaced pump is indeed fully worn out and maxed out its original installation cost.
"Said Mr Khaw: 'If it were well-maintained, the reservoir should be empty before rain starts to flow. But it overflowed. The pit had not been maintained properly.'
He later revealed that the Land Transport Authority and SMRT had in fact, on Sep 29, made a decision to replace the pumps."
Khaw Boon Wan on NSL flooding: SMRT maintenance team 'failed us'
Khaw Boon Wan on NSL flooding: SMRT maintenance team 'failed us'
Train operator SMRT has apologised for the flooding at the Bishan-Braddell MRT tunnel which disrupted services along the North-South Line on Oct 7 and 8. Dr Zhou Yi, a council member at the Institution of Engineers in Singapore, says the situation was preventable.
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By Justin Ong
16 Oct 2017 06:30PM
(Updated: 16 Oct 2017 11:07PM)
SINGAPORE: Transport Minister Khaw Boon Wan on Monday (Oct 16) said the SMRT maintenance team in charge of the anti-flood system at Bishan station had “failed us”, in his first public address on the major North-South Line (NSL) tunnel flooding incident two weekends ago.
On the evening of Oct 7 - a Saturday - torrential rainwater seeped in at Bishan station, causing the underground tunnel leading to Newton station to be submerged up to waist level.
SMRT had to cut off trackside power supply as a safety precaution, causing service on six stops across the NSL to be disabled for about 20 hours. More than a quarter of a million commuters were affected.
It was Singapore’s first disruption due to flooding and one of SMRT’s worst breakdowns in recent history, prompting much public unhappiness.
The incident was “sad and unnecessary” - but preventable and should not have happened, said Mr Khaw.
“We are all sorry it did ... Whatever follow-up action which needs to be done, has already started. Nothing has been covered up.”
“The incident has pushed back the recovery of public confidence in us,” he acknowledged.
Mr Khaw said Singapore’s MRT tunnels were designed to handle local weather and cope with “very extreme storms far more severe than the last few weeks”.
“The bottom line is they should not have been flooded. But on Oct 7, the stretch at Bishan and Braddell stations did.”
“There are standard anti-flooding systems with huge stormwater sump pits,” he explained. “Our findings show that the anti-flooding system there was poorly maintained.”
“In simple terms, the stormwater pit can hold more than 5,000 cubic metres of rainfall ... During that period over the catchment area, rainfall could not have exceeded 700 - let’s stretch it, 1,000 cubic metres.”
Said Mr Khaw: “If it were well-maintained, the reservoir should be empty before rain starts to flow. But it overflowed. The pit had not been maintained properly.”
He later revealed that the Land Transport Authority and SMRT had in fact, on Sep 29, made a decision to replace the pumps.
“So we are late by a few days. Had they proceeded to replace (the pumps) this thing might not even have happened.
"But I suppose that is life."
“WE’VE MADE SERIOUS IMPROVEMENTS”
The Transport Minister said energies had been focused on rails and train signalling systems instead - which he pointed out had improvements to show.
“At the beginning I said to give me four or five years. We are at the mid-point now,” he stated.
“We wanted to close the gap with Taipei’s benchmark of 800,000 km without incident ... We have made serious improvements, we have exceeded next year’s target (of 400,000km) and that’s why I was confident enough to say let’s go for 1 million.
“But I knew Singaporeans couldn’t relate, because they still hear delays here and there because of resignalling.”
The main reason for this, said Mr Khaw, can be traced to two major projects ongoing at the same time - improvements to existing lines and resignalling for the NSL.
“I did say the resignalling would have tonnes of problems. I said so in public, to bear with us,” he said.
“So even when you evaluate our performance in resignalling, we have done well. That’s why I’m concerned when media reports conflate the two projects and draw wrong conclusions.”
Read more at http://www.channelnewsasia.com/news/singapore/khaw-boon-wan-on-nsl-flooding-smrt-maintenance-team-failed-us-9315666