Saturday 19 May 2012

MRT breakdown COI: Day 23

'Realistic' MRT drills planned
LTA to test operators' responses to disruptions
By Goh Chin Lian, The Straits Times, 18 May 2012

UP TO two major emergency drills are being planned at the end of this year to test the responses of public transport operators in the event of train disruptions. The drills will have greater realism than the table-top discussions of hypothetical scenarios held before the December breakdowns, the Land Transport Authority's (LTA) director of public transport regulation Yeo Teck Guan said yesterday.

Other steps to improve emergency preparedness include timelier post-incident reviews so that lessons can be quickly gleaned and disseminated, as well as having just one document listing the actions that operators must take in an emergency, he said.

He was being questioned by the Committee of Inquiry about how the LTA ensured the operators' emergency preparedness.

Mr Yeo told The Straits Times later that the LTA may hold one exercise involving SMRT, which runs the North-South, East-West and Circle lines, and another exercise involving SBS Transit, which operates the North-East Line. No further details were given, although the level of realism is not expected to reach the scale of a national-level terror exercise in 2005, involving the evacuation of 3,400 commuters travelling on the MRT on a Sunday morning.

Mr Yeo revealed that drills are done when a new MRT line is about to open, and regularly over a four-year cycle: The LTA holds internal exercises in the first and second year, and then exercises with the operators in the third and fourth year. Until recently, the scenarios were not specific to train disruptions, but more generic, like a construction site mishap affecting train and bus services.

Mr Yeo, explaining the need for more realistic exercises, said previous table-top discussions did not reflect reality. People trained to deal with emergencies may also react differently in real crises. As another check on emergency preparedness, the LTA will no longer wait for a full probe to end before reviewing the management of the incident. The LTA will meet the affected operator within two weeks of its occurrence and share learning points with the other operator.

It took more than two months to review a disruption on the Circle Line that affected 26,000 commuters on Sept 20 last year. Minutes of the Dec 2 review meeting between the LTA and SMRT, submitted to the inquiry yesterday, showed that the areas found lacking were similar to the Dec 15 and 17 disruptions. They include not providing enough information to commuters about the disruption, and inadequate bus bridging services to take stranded commuters from affected MRT stations.

Recommendations given at that meeting, such as using social media to broadcast the disruption and giving commuters free travel on buses, were adopted after the December breakdowns.

The Inquiry members also made known their views on areas in which the LTA could improve.

Director of Prisons Soh Wai Wah said he got the impression that the emergency responses which the LTA expected of the operators were laid out 'here and there' in different codes of practices. Agreeing, Mr Yeo assured him that the measures will be combined into a single document.

SMRT chairman Koh Yong Guan told the Inquiry last Friday he was uncomfortable with its engineers getting inadequate attention in salaries and other aspects, even though SMRT's core business was trains. Mr Yeo agreed that it was good to have such indicators to arrest problems before they arise.

But he stuck to his guns on one issue: Chief District Judge Tan Siong Thye and Mr Soh felt that the LTA's requirement for its public transport crisis management team to meet within two hours of activation was too long, as most of the crisis handling takes place in the first hour.

Mr Yeo said arrangements are in place for the operators to seek help from the LTA's nerve centre. LTA's higher management can also be reached on their cellphones if a strategic decision is needed.

The team's main task is to come up with contingency plans in an extended disruption, he added.

More secure design of rail claws rejected as 'original one worked'
By Goh Chin Lian, The Straits Times, 18 May 2012

THE designer of the claws that fell off in the December MRT breakdowns has explained why a more secure design was rejected 25 years ago.

British company Brecknell Willis & Co's engineering director David Hartland said MRTC - the rail builder that later became a part of the Land Transport Authority - felt that the original claws that kept the power-supplying third rail in place had worked, and was 'nervous' about using a new design untested on other rail systems.

'Having found something that works, it's better not to change it,' he said yesterday.

Brecknell Willis had in 1987 presented to the MRTC the new claw with a split pin locking system that prevented dislodgement even under 'severe vibration'.

But MRTC, he said, had rejected it and stuck to the original claw designed in 1985. Some of these claws had spring clips to help them withstand vibration.

In last December's breakdowns, third-rail claws were found dislodged, causing the third rail to sag, disrupting power supply to the trains. SMRT has said it intends to change all claws to the latest fifth-generation ones that use cast stainless steel and have a secure bolt fitting.

These are used in the Boon Lay and Changi Airport MRT extensions, and the Circle Line.

But Mr Hartland said SMRT handed him a broken piece of the fifth-generation claw on Wednesday night to take back to Britain to check for material defects. He said this was the first time the claw had failed.

He attributed it to 'heavy mechanised overload, probably not due to normal service'.

When contacted, SMRT declined to say what had led to the failure. But The Straits Times understands that witnesses lined up could shed light on what happened.

Cables on NEL 'need to be replaced'
Test lab recommends precautionary move to prevent repeat breakdown
By Christopher Tan, The Straits Times, 18 May 2012

STEEL cables that help hold the power line in place on the North-East MRT Line (NEL) may all have to be replaced soon.

The cables were at the centre of a 10-hour disruption to train services on March15, after two of them were found to have snapped.

Tests on these two cables have been completed, and the laboratory which conducted them is recommending all such cables along the 20km line be changed.

The Straits Times understands that this is a precautionary measure to prevent a repeat of the breakdown, which affected about 90,000 commuters using the nine-year-old MRT line.

That morning, before train services started, two cables south of Outram station were discovered to have snapped. The cables - each measuring no more than 1cm thick - were part of a counterweight system that kept overhead power lines supplying electricity to the trains taut and aligned.

Once the cables broke, the concrete weights attached to them fell, and two overhead wires supplying power to the trains sagged, one to the ground and the other in mid-air.

No train could pass through and services on five stations from Dhoby Ghaut to HarbourFront were disrupted till about 4.30pm.

The cables that snapped were sent to TUV SUD PSB - a Singapore-based test lab - for analysis.

A senior consultant at the laboratory who is in charge of the investigation told The Straits Times that the test report recommends that NEL operator SBS Transit change the cables to a stronger type but of a similar thickness.

TUV would not say more, citing 'client confidentiality'.

SBS Transit spokesman Tammy Tan yesterday confirmed that TUV SUD has completed its investigation and submitted its report to the company.

She said SBS Transit would be reviewing the test results and recommendations with the Land Transport Authority. The authority - which had embarked on its own investigation of the incident - said it needed time to study the TUV SUD report. Its own probe, it said, was still under way.

Ms Tan said there are 182 such cables along the North-East Line.

The incident puzzled engineers. The cables were each attached to a counterweight of around 800kg, but SBS Transit had said then that they were designed to withstand 10 times that weight. Sources said the test results pointed to 'inherent defects' in the cables that caused them to give way.

Safety specialist S. L. Chen, 58, said 'inherent defects' meant either the quality of material was sub-standard, or the manufacturing process was not up to scratch.

Mr Chen, who has worked in the aviation industry for 21 years and spent another 14 as a safety specialist, said 'there is no harm in selecting an even stronger cable' just to be on the safe side.

He said the operator should also dismantle cables at random to conduct 'load testing' on them 'at least once every four years'. He said that is the industry practice for cables used in lifting machinery such as cranes. That is on top of regular visual checks.

Load testing means subjecting a component to either normal or higher-than-normal stress levels to see how it holds up.

The cost of replacing the cables is not expected to exceed $1 million, but it could be a labour-intensive operation that spans several weeks as the work can only be done after service hours.

The test results come amid an ongoing high-level inquiry into two other train disruptions in December, this time on the North-South Line.

The Straits Times understands that a decision on the cable replacement on the NEL is unlikely before the inquiry wraps up, probably in two weeks' time.


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