Thursday, 16 November 2017

MRT collision: Signal fault to blame as trains collide at Joo Koon Station

Signal fault to blame for Joo Koon MRT collision
Stalled train hit by another train at Joo Koon after software glitch; 29 injured
By Maria Almenoar, Assistant News Editor and Adrian Lim, Transport Correspondent, The Straits Times, 16 Nov 2017

An unprecedented software glitch in the signalling system of the East-West Line resulted in a stalled MRT train being hit from behind by another one at Joo Koon station yesterday morning.

This resulted in injuries to 29 people, three of whom were still in hospital yesterday evening.

The collision took place at 8.20am during the morning peak hour and disrupted train services between Boon Lay and Tuas Link stations through the day.

Train services between Joo Koon and Tuas Link stations will remain suspended today while the authorities carry out their investigations. Bus bridging services will be provided to the affected passengers. Other trains on the East-West Line will run at slower intervals.

In the accident yesterday, the first train had pulled into Joo Koon station when it stalled because of an anomaly in the signalling system, and its passengers were offloaded, save for a solitary SMRT staff member who remained on board.

The second train, which had stopped more than 10m behind and was carrying more than 500 passengers, unexpectedly lurched forward and collided with the first train.

At a press conference later in the day, Land Transport Authority (LTA) and SMRT officials explained that the signalling system had mistakenly profiled the stalled train as a three-car train, instead of the six-car train that it really was.

As a result, the second train which had stopped 10.7m behind the first "misjudged the distance" between the two, resulting in a collision.

"It is an awful day today. Commuters were inconvenienced, and some even injured. We are deeply sorry for that," said Transport Minister Khaw Boon Wan, who showed up at the press conference and spoke to reporters after it was over. SMRT chief executive Desmond Kuek was present, but did not speak.

The incident was the latest in a series of mishaps that have hit the train operator, including tunnels between Braddell and Bishan stations being flooded last month.

Sharing their preliminary findings yesterday, SMRT and LTA said the first train departed Ulu Pandan depot with a software protection feature, but this was "inadvertently removed" when it passed a faulty signalling circuit.

Passengers got off the stalled train and the second one halted at the correct, safe stopping distance behind it. However, the second train moved forward a minute later when it could not properly detect the stalled train as having six cars.

Mr Alexandru Robu, 35, who was in the second train, described how it came to a sudden halt after its impact with the first one, causing passengers to lose their balance and fall. "I have experienced sudden stops before on the MRT, but this time, it was really bad," said Mr Robu, a service coordinator.

One MRT employee on each train and 27 commuters were hurt. Several were taken to hospitals, and most were discharged with minor injuries. The remaining passengers were taken off the train through the driver's cabin at the front - a process that took some time.

Thales, the firm supplying the new signalling system for the North-South and East-West lines, said it had never encountered a glitch similar to yesterday's before.

Mr Khaw said after the press conference: "Thales is confident of their system, but I advised the team, let's play doubly safe, where safety is involved, that is why I want them to suspend the Tuas West Extension tomorrow, so we have a whole day to do a thorough check before we resume the Tuas West Extension."

Asked if a committee of inquiry will be convened to look into this, Mr Khaw said the investigation should be allowed to take its course.

On whether commuters' confidence in the MRT system had been undermined following yesterday's accident and last month's MRT tunnel flooding, Mr Khaw said: "Obviously people will be upset... I am equally upset."

Additional reporting by Christopher Tan and Tan Tam Mei

Joo Koon collision: 'It happened so quickly... It was a really big stop'
Sudden impact threw many off balance; one door later opened to let passengers leave train
By Aw Cheng Wei, Tan Tam Mei and Adrian Lim, Transport Correspondent, The Straits Times, 16 Nov 2017

Service coordinator Alexandru Robu, 35, was on his way to work yesterday morning when the train he was on collided with a stationary one in front of it at 8.20am.

"It happened so quickly," said Mr Robu, who was standing in the carriage closest to the collision. "It was a really big stop, and we heard a loud sound."

The sudden stop threw him off balance. He tried to break his fall with his hand and landed on the ground. He estimated that 30 people around him also fell.

"Some people fell on top of each other," said Mr Robu, who is from Moldova in eastern Europe. "Everyone took about one to two minutes to recover."

An announcement then came on informing commuters that help would be arriving in about 20 minutes.

The plan was to tow the stationary train away before the second train could pull into the platform.

It was then that Mr Robu noticed a man on the ground holding his head.

"He did not look good," said Mr Robu. He went over to the man, who started to look unresponsive.

He said: "I tried to keep him engaged by talking to him and making sure that he was okay."

At this time, some people in the train were calling for an ambulance. Mr Robu pressed the emergency button to ask the driver if the first door could be opened to let the man out for fresh air.

It was starting to get stuffy in the train. "There was no air-con," Mr Robu said. "People were also getting anxious."

About 20 minutes later, a second announcement came on to inform passengers that the first door would be opened to let them out.

People left in a proper fashion, guided by SMRT staff and police officers. Mr Robu stayed with the injured man, who was put in a wheelchair once he got out of the train, and made sure he received medical attention.

Mr Samuel Ng, 48, a sports adviser who was getting off another train at about 8.50am, said that he saw people queueing to get out of the second train.

He said: "There was no chaos, no shouting. When I went downstairs, there was also a very long queue at the control station."

Commuters on the platform said that they heard a dull thud before people started screaming.

Mr Ganeshan Sivalingam, 38, who was waiting at the platform for the train to Tuas Link, said he heard a "bang".

When he went closer, he saw that the blocks of metal at the front of the second train had hit the rear of the stationary train.

Station operators then ushered him and other commuters out of the station, where he got on a bus to work. He said that the train station was "not very crowded", and it took about five minutes for him to leave the station.

Parts of the platform had been cordoned off when Mr Robu left the train. Ground control staff from SMRT, and officers from the Singapore Civil Defence Force and the police directed commuters to leave the train station.

The platform reopened at about 11.20am, and trains were running on only one side of the tracks.

When reporters went to the National University Hospital and Ng Teng Fong General Hospital (NTFGH) in the early afternoon, the injured passengers were already being treated.

The Straits Times understands that some had already been discharged at that time.

Businessman Lim Kim Hock, 56, who runs a switchboard company, sent one of his workers, Mr Tan Ban Heng, 37, to NTFGH when he saw that Mr Tan's kneecap had become bloody and swollen.

Mr Lim said he wanted to see Mr Tan's injuries when he found out that he was in the accident.

He said Mr Tan had earlier declined medical help because the injury "did not look that bad". Mr Lim said: "Once I saw the injury, I told him he must go to hospital."

SMRT staff to help with compensation queries
By Maria Almenoar, Assistant News Editor, The Straits Times, 16 Nov 2017

Passengers who were injured in the Joo Koon station train collision may approach staff at any SMRT station to ask about compensation.

Train operator SMRT said it would help any passengers affected even if they were not taken to the hospital immediately by its team.

SMRT said that at about 7.30pm yesterday, Ng Teng Fong General Hospital had admitted an injured passenger as a walk-in patient.

This brought the total number of injured to 29, including two SMRT employees.

The injured were treated at Ng Teng Fong General Hospital, where two remain warded for observation, and National University Hospital, where one passenger is still warded.

All injured passengers were on board the same train which had collided with a stationary train. The moving train was carrying 517 people, including its driver.

The injuries included bruises and fractures, with one passenger hitting the grabhold when the train lurched forward. One commuter broke a tooth, while another fainted during the incident.

An assistant station manager, who was on board the stationary train, was also injured after helping passengers alight.

The Ministry of Transport, Land Transport Authority and SMRT said they were in touch with injured passengers to offer them necessary assistance.

Joo Koon collision: 'Inadvertent removal' of software fix led to collision
LTA investigating why this happened, together with SMRT and firm supplying signal system
By Adrian Lim, Transport Correspondent, The Straits Times, 16 Nov 2017

Software meant to fix a known problem in the East-West Line's new signalling system had been "inadvertently removed" and this led to the collision between two trains at Joo Koon station yesterday morning.

Sharing these details at a press conference 10 hours after the incident, the Land Transport Authority's (LTA) deputy chief executive Chua Chong Kheng said that it is investigating why this happened, together with operator SMRT and Thales, the French company supplying the signalling system.

Also present were Transport Minister Khaw Boon Wan, SMRT chairman Seah Moon Ming and SMRT group chief executive Desmond Kuek, but they were not part of the panel leading the press conference.

Mr Chua, who chaired the press conference, together with SMRT and Thales officials, revealed that earlier tests uncovered how an interruption in communications between onboard computers on a train would result in it being wrongly identified as a three-car train, rather than one with six cars.

To fix this on the East-West Line's new signalling system - which is used on the Tuas West Extension that opened in June - a software protection module was developed by Thales.

However, when a train passed by a faulty track circuit yesterday, this software module was "inadvertently removed". This caused it to be identified as a shorter, three-car train.

This subsequently led to an-other train behind "misjudging the distance" to the one in front, causing the collision, in which 27 commuters and two SMRT staff were injured.

Thales, which has installed signalling systems for metros in cities such as Hong Kong and Vancouver, described the glitch as unprecedented.

Mr Chua also said the same type of signalling system, which has been implemented on the North-South Line this year, has "proven to be working very well".

While the Tuas West Extension - a four-station, 7.5km-stretch that extends from Joo Koon station - is using Thales' new signalling system, the rest of the East-West Line is on an older 30-year-old system.

"We are in a stage where we are going through a transition of trying to implement the new signalling system... this (faulty) signalling circuit, as we understand from Thales, was going through the process of being changed," Mr Chua said.

He added that it was "too early" to say whether yesterday's glitch will derail original plans to switch the rest of the East-West Line to the new signalling system before the end of the year.

The new signalling system allows trains to arrive at up to 100-second intervals, instead of the current 120 seconds.

Yesterday's collision occurred as the first train was about to move off from Joo Koon station. Before that, it had stopped there to offload all passengers, due to a separate signalling problem.

While the train and platform screen doors were opened for passengers to get off, the signalling system would prevent another train from pulling into the station and hitting it, said Mr Chua. The second train initially stopped about 10.7m - the correct safety distance - behind the first.

Experts said yesterday's accident was a worrying one.

Assistant Professor Andrew Ng from the Singapore Institute of Technology's (SIT) engineering cluster said that if the trains were moving on the tracks, and the front one was mistaken as a three-car train, the rear one could misjudge the distance, potentially leading to a collision.

Assistant Professor Zhou Yi, also from SIT, said that suspending operations on the Tuas West Extension today is a good move and puts the safety of commuters first.

"We need to be very cautious moving ahead," Prof Zhou said, adding that SMRT and LTA should request for Thales to further open up its systems for a better understanding.

Mr Ang Hin Kee, deputy chairman of the Government Parliamentary Committee for Transport and an MP for Ang Mo Kio GRC, said it was "important to quickly identify the cause of the collision and to provide assurance to all commuters that the matter is being addressed".

MRT collision: No train service on Thursday (Nov 16) between Joo Koon and Tuas Link
By Maria Almenoar, Assistant News Editor, The Straits Times, 16 Nov 2017

Train service between Joo Koon and Tuas Link stations was suspended on Thursday (Nov 16) for the authorities to carry out investigations, after two trains collided on Wednesday.

Bus bridging services were provided for affected passengers.

Commuters should also expect trains on the North-South and East-West lines to arrive at slower intervals, the authorities said on Wednesday.

The current two-minute interval between trains will be slowed down to between 2½ minutes and three minutes.

The Land Transport Authority (LTA) said that this was being done as an interim safety precaution after Wednesday morning's collision, which left at least 29 people injured.

"We want to make sure we understand fully what the cause is and that we have the right measures in place. Once we know that, we will be able to revert back to the previous... operations," LTA's deputy chief executive for infrastructure and development Chua Chong Kheng said at a press conference.

In a tweet at 4.43am on Thursday morning, SMRT said free bus services were available between Joo Koon and Tuas Link stations. It also said that trains were running as per normal on the North South Line.

Investigations so far found that a glitch in the new communications-based train control system wiped out a safety software feature when the first train passed a faulty circuit.

The French firm which provided the signalling system, Thales, said that this was the first time such an incident had happened.

"In fact, the CBTC (communications-based train control) is on record as one of the safest systems. We have never actually had a collision," said Thales representative Peter Tawn.

He added that it was unlikely, but the company has not ruled out increasing the safety factor - or the buffer distance - between trains, and a decision would be made once the investigations are completed.

The current safety factor ranges from about 10m to 50m, and is calculated based on a number of parameters, including the gradient of the track, Mr Tawn explained.

In Wednesday's incident, the trains had adhered to the safety buffer of 10.7m before the train at the back lurched forward and collided with the one at the station platform.

SMRT's senior vice-president of rail operations for the North-South and East-West lines, Mr Alvin Kek, said that the operator was putting "additional checks and controls in place" as a safety precaution.

"We have told train captains to be a lot more vigilant... even if (the train is) driven in the automatic mode," he added, saying that drivers are trained to deal with such emergencies.

Additional information will also be made available to drivers in their train cabins to help them assess such situations better.

LTA added that trains will also go through an additional layer of control measures and manual checks before they are deployed.

Joo Koon collision: Signal failure hits confidence
By Christopher Tan, Senior Transport Correspondent, The Straits Times, 16 Nov 2017

The word "ponding" comes to mind. It was used by national water agency PUB to describe massive floods which hit Singapore in December 2011.

Dr Vivian Balakrishnan, then Minister for the Environment and Water Resources, took issue with that in Parliament the following month.

"PUB should not have used the word 'ponding'. As far as I am concerned, I call a spade a spade. A flood is a flood," he said, echoing public sentiment.

The Land Transport Authority (LTA) and rail operator SMRT described yesterday's collision between two trains in Joo Koon station as an incident where one train had "come into contact" with another train, which conjures the imagery of a nudge.

SMRT repeated the same phrase on its Facebook page.

"This morning at 8.18am, a train heading in the direction of Tuas Link station stalled at Joo Koon station. At 8.19am, a second train stopped behind the first faulty train. At 8.20am, the second train moved forward unexpectedly, and came into contact with the first train."

It was only at 7.42pm that an updated statement by the LTA described the incident as a "collision".

Their earlier reluctance to call a spade a spade severely underplays the seriousness of an accident which left 29 people with injuries.

First and foremost, trains are not supposed to collide, or even come into contact with each other (unless one train was used to push out another disabled one, as has often been the case lately).

That is what the signalling system is for. It keeps a safe distance between trains, acting like an invisible, impenetrable barrier between locomotives.

No metro system can operate without a reliable signalling system, which is actually the eyes of the network.

This is why when trains sense there is something amiss with the signalling system, or there is some interference, they will activate their emergency brakes. It is safety protocol - to be safe first rather than sorry later.

Usually, a train cannot pull into a station when the one in front of it has not left the station. This is why trains sometimes stop in the middle of a tunnel, and passengers are left wondering why. More often than not, it is precisely because the train in front has stopped for too long. So, instead of breaching the invisible barrier, the second train has to stop too, even if it is in the middle of nowhere.

That a train has somehow managed to breach this safety barrier is worrying, to say the least. At Joo Koon, trains switch over from the old fixed block signalling system to the new moving block system.

Investigations have uncovered that the glitch which caused the collision yesterday lies with the new system.

The new signalling system has been having numerous technical issues here, but none compromising safety until yesterday.

So, it is regrettable indeed that SMRT and the LTA have chosen such a light term earlier in the day to describe the incident. Like the tunnel flooding which took place just last month, it is not trivial. A signalling failure can have grave consequences.

You do not need to have a vivid imagination to think of what might have happened if either train had more passengers. And if a "coming into contact" nudge can result in 29 people getting hurt, think of what a high-speed collision would entail.

In the 30-year history of Singapore's MRT system, there has been only one other train collision which resulted in injury. In 1993, one train ran into another at Clementi station, resulting in more than 150 people getting hurt. The incident triggered a public inquiry, which found that an oil spill on the tracks had compromised the stopping ability of the second train. It was not a signalling issue.

SMRT and LTA have to come out with full transparency on how yesterday's incident happened, and what concrete steps are to be taken to prevent a recurrence.

They will no doubt do so, just as they did after the Oct 7 tunnel flooding. Reams of information will be made public.

And herein lies the rub: How does seeking to minimise yesterday's incident help reassure a public whose confidence has been shaken repeatedly since 2011 that the issues are being put right?

A sagging power-supply rail brought the North-South Line to a standstill on the evening of Dec 15 that year, and then again on the morning of Dec 17, as SMRT failed to detect and rectify the damage completely. Affecting more than 250,000 commuters, it was the biggest disruption then.

Another public inquiry was convened, and SMRT reshuffled its top management.

A power-supply trip caused both the North-South and East-West lines to fail on July 7, 2015, affecting about half a million commuters, the highest number on record here as of now. The LTA said a salt-caked insulator near Tanjong Pagar station was the cause.

A power trip at one of the network's substations caused the western sector of the North-South and East-West lines, parts of the Circle Line, as well as the Bukit Panjang LRT system to fail on April 25 last year. The unprecedented four-line disruption was suspected to have been caused by cable works on the East-West Line's Tuas West extension.

On March 22 last year, two SMRT trainee technicians were killed on the tracks near Pasir Ris station. Investigators found that a slew of standard operating procedures had been breached. The Manpower Ministry said SMRT had been flouting such guidelines since 2002.

On Oct 7 this year, tunnels between Braddell and Bishan stations were flooded, with water reaching waist level at some points. While preliminary investigations found that the crew in charge of maintaining the flood-prevention system at Bishan had not been doing their job properly and had in fact falsified work logs, the various individual key components such as pumps and switches were found to be in proper working order.

Even as Singaporeans were coming to terms with the flooding, yesterday's train collision took place.

Clearly, enough is enough.


* Joo Koon-Gul Circle link to remain closed till mid-2018
Early closures on East-West Line also on the cards to speed up works in wake of collision
By Christopher Tan, Senior Transport Correspondent, The Straits Times, 22 Nov 2017

The fallout from last week’s train collision at Joo Koon station will echo for several more months. It will mean the end of seamless journeys for commuters travelling between Tuas and Pasir Ris on the East-West Line for at least up to June next year.

There will also be early closures along stretches of the East-West Line on Fridays and Saturdays, and late openings on Sundays from Dec 8 to 31 as resignalling works get speeded up to finish by June instead of the end of next year.

This will affect 17 stations from Tiong Bahru to Tuas Link, as well as Bukit Batok and Bukit Gombak stations on the North-South Line.

On Dec 10 and 17, which are Sundays, these stretches will also close for the whole day.

The changes were flagged after it was revealed that the collision was caused by compatibility issues between an old and a new signalling system. To avoid the risk of a repeat incident, the two systems will remain separated till next June.

That means commuters travelling between Tuas and Pasir Ris on the East-West Line will not have a seamless journey for a while. They will have to get off at Joo Koon and take a free bridging bus service to the next stop at Gul Circle, to continue westwards on a line which runs on the new signalling system.

Likewise, on the return trip, they will have to get off at Gul Circle and take the bridging bus service to Joo Koon to continue eastwards.

Stony-faced representatives from SMRT, regulator Land Transport Authority (LTA) and signalling system provider Thales met the media yesterday to reveal their findings on the Nov 15 collision which left 38 people injured. Thales official Millar Crawford said: “We apologise to commuters, in particular to those who were injured.”

Speaking to reporters after the briefing, Transport Minister Khaw Boon Wan said: “When we launched Tuas West Extension, we intended it to be a seamless link from Pasir Ris to Tuas Link. In hindsight, of course, this has introduced a lot of complications... Still, Thales could have done better.”

It has been decided to have “complete separation” between the old and new signalling systems. The old system was originally to be phased out by the end of next year. But to minimise impact on commuters, it is now targeted to end by June.

Meanwhile, the shortened service hours from Dec 8 to Dec 31 will affect 20,000 to 30,000 people, the LTA said, adding that other stretches of the East-West Line will see reduced service hours in the first half of next year too.

The briefing on the Nov 15 incident revealed that a glitch on trainborne signalling equipment disabled a “bubble” which acts like an invisible barrier to prevent trains from colliding. The system then created another bubble.

But the second bubble was disabled when the train passed Clementi station. A trackside device which was modified two days earlier to connect the two signalling systems failed, resulting in compatibility issues between train and track.

At Joo Koon, this train which no longer had the protection of the bubble – rendering it almost invisible to other trains – was hit by another.

Mr Khaw said the collision – as well as the flooding incident – have “shattered” the confidence of commuters. “But it has happened, and we have to get over it and regain the public’s confidence.” Upping the reliability of the whole system would be key to this end, he said.

Commuters regret inconvenience but hopeful it will pay off
By Lim Min Zhang, The Straits Times, 22 Nov 2017

Commuters said the planned shorter operating hours for some MRT stations next month would be an inconvenience, but it would be worth it if the maintenance work to be done during that time paid off.

At a press conference yesterday, the Land Transport Authority and SMRT announced that 17 East-West Line stations and two North-South Line stations - Bukit Gombak and Bukit Batok - would have shorter operating hours on most Fridays, Saturdays and Sundays next month.

On these days, service will end at 11pm on Fridays and Saturdays, and start at 8am on Saturdays and Sundays, to facilitate resignalling and other renewal/maintenance works.

Project engineer Desiree Tiangco, 27, believes that the shorter hours would be inconvenient, especially for those who work on weekends. She works every Saturday, travelling from Yew Tee to Jurong East by 7am. She said she might have to take a taxi from Bukit Gombak to Jurong East for a while.

Ms Tiangco said: "The trains here are the No. 1 transport option for many people, so this is a sacrifice for everyone, but I hope the trains will be better after this."

Another weekend worker, Ms Grace Fu, 60, a supermarket retail assistant who works in Clementi, will have to take two buses instead of the train for her journey from Bukit Gombak. "Although there has been many delays lately, trains are still faster," she said.

Engineer Ken Lim, 31, who commutes from Clementi to Tai Seng for work, said people who have difficulty getting around might find it more difficult to navigate the extra crowds on buses now.

Yesterday, it was also announced that the suspension of train service between Joo Koon and Gul Circle stations will remain until mid-2018.

Sales administrator Cindy Tan, 33, who works near the latter, said: "I am disappointed with this disruption because we only managed to enjoy the Tuas West Extension for about five months before the collision happened last week. There is usually a jam near Gul Circle in the morning and evening peak hours, so it is a headache... that this non-service will continue until next year."

Mr Sitoh Yih Pin, chairman of the Government Parliamentary Committee for Transport, said the early closures were "definitely worth a try" if they allowed maintenance work to be completed faster, thus reducing the frequency of delays.

"This could alleviate some of the frustrations our commuters face as we work hard towards completing the resignalling works," he said.

Protective 'bubbles' became disabled, causing collision
Firm behind signalling system takes responsibility for part in accident
By Adrian Lim, Transport Correspondent, The Straits Times, 22 Nov 2017

Protective "bubbles" meant to keep trains at a safe distance from each other were inadvertently disabled on Nov 15 before two trains collided at Joo Koon MRT station.

French company Thales, which has taken "full responsibility" for its part in the collision, said it happened because of an "unexpected" problem in the interface between the old and new signalling systems of the East-West Line (EWL).

Officials from SMRT, Thales and the Land Transport Authority (LTA) explained how the Thales Communications-based Train Control (CBTC) system works.

On the day of the accident, the system - which allows trains to run closer together and arrive at shorter intervals, and is already in use on the North-South Line (NSL) - was running on a passive mode between Pioneer and Pasir Ris MRT stations to collect data.

At that point, trains were operated and controlled using the older 30-year-old fixed-block system.

Prior to the collision, an eastbound train, which had been launched from Ulu Pandan Depot, encountered an abnormal condition with the CBTC equipment on board. A protective bubble that helps keep trains at a safe distance from one another became disabled as a result.

LTA deputy chief executive Chua Chong Kheng said it happened because the two onboard computers experienced a loss of communication.

A second bubble which should have immediately replaced the first became unexpectedly disabled as well that day. This happened after the train passed a track circuit which had yet to be modified for the CBTC system, at Clementi.

The abnormal condition of the train's CBTC equipment was discovered at Pioneer MRT station, where a switchover to the CBTC was required. The CBTC is used to control trains between Pioneer and Tuas Link and is operational there as part of the Tuas West Extension (TWE), which opened in June.

After the CBTC problem was detected, the train was switched to be driven in manual mode to Joo Koon station. This meant the driver had to manually open the platform screen doors at Joo Koon. When the doors are opened manually, another train will not be able to enter the station. A second train with 517 passengers was then waiting 36m behind.

But when the platform screen doors were manually closed to allow the affected train to move off, the second train, which was running in automatic mode, moved forward as it could not detect any protective bubble around the first train, resulting in the collision.

Mr Alvin Kek, senior vice-president for rail operations at SMRT, said the 10 seconds before the collision was "insufficient" for the driver onboard the second train to react.

Thales said that it has conducted an "intensive exercise" to check its systems on the NSL, EWL and TWE to ensure that there will not be similar circuits removing protective bubbles from trains. 


Thales, firm behind signalling system could have done better: Transport Minister Khaw Boon Wan
By Adrian Lim, Transport Correspondent, The Straits Times, 22 Nov 2017

The company supplying the new signalling system for the East-West Line (EWL), on which a train collision occurred last week, "could have done better", Transport Minister Khaw Boon Wan said yesterday.

But Mr Khaw also acknowledged that French firm Thales faced "challenging situations", as only a small segment of the EWL, called the Tuas West Extension (TWE), used Thales' system, while the bulk of the line ran on an older signalling system.

"In hindsight, this introduced a lot of complications because you have two stretches, each running on different signalling systems," Mr Khaw told reporters.

Due to a problem in the interface between the old and new signalling systems last Wednesday, two trains collided at Joo Koon MRT station, causing injuries to 38 people.

Mr Khaw said the parts of the EWL running the old signalling system and the stretch running the new system will now be kept separate until the entire line can migrate to Thales' system by the middle of next year.

Asked about public confidence in the new signalling system, he said: "Inevitably, the confidence will be shattered by events like this, but it has happened, and we have to get over it and regain the public's confidence, which means back to the same old job - we have to raise reliability."

Lessons to learn from Joo Koon collision
By Christopher Tan, Senior Transport Correspondent, The Straits Times, 22 Nov 2017

Just like the MRT tunnel flooding incident last month, the train collision at Joo Koon station on Nov 15 was caused by not one, but two failures.

Two concurrent glitches - what are the chances of that? Yet, as Murphy's law dictates, what can go wrong will go wrong.

In retrospect, the collision - unfortunate as it was - is a powerful lesson as signalling failures can have far more dire consequences than 38 people being injured.

Hence, the decision to separate the old and new signalling systems - which have failed to work together - is a prudent one, even if it means commuters using the East-West Line will not have a seamless journey to and from the Tuas West Extension for at least seven more months.

The risk of another collision, no matter how remote, is just not worth it.

Why, then, did we have a line running on a new signalling system coexisting with one running on an older and completely different system? Would it not have been neater - and safer - to wait until the current East-West Line had changed to the new system?

Ideally, that should have been the case, especially if early planning came with prompt delivery of plans made.

The decision to upgrade to a new signalling system - which is not only safer but also allows the network to increase its capacity significantly - was taken 20 years ago.

In July 1997, then SMRT managing director Kwek Siew Jin announced that the North-South and East-West lines would be upgraded. The project would have cost $100 million and been completed by 2002.

Somehow, that plan was not executed until recently.

Resignalling on the North-South Line will now be completed by next month, and that on the East-West Line by June next year.

If SMRT had stuck to the original timeline for resignalling, many of the problems and challenges our rail network faces today would be far less severe.

But even as SMRT and the Land Transport Authority catch up on renewing ageing assets - from the power supply "third rail" to rail sleepers to the signalling system - plans to expand the network cannot and should not be put on the backburner.

The complete asset renewal will be completed only by 2024, which is quite a long way off. Clearly, it is not tenable to hold off new lines until then.

The Tuas West Extension, for one thing, has been a long time coming. Tens of thousands of Singaporeans work in the industrial hub which has until recently been poorly served by public transport.

French signalling system supplier Thales says it has done projects which involved marrying old and new signalling systems on a live network. And it must have been confident to do the same here.

Alas, its confidence has been misplaced, as events on Nov 15 have demonstrated.

Rather than having another go at making the two signalling systems work with each other so that trains transiting from one to the other do so without incident, the decision has been made to separate the two systems.

It is a loss of face for those involved in the resignalling project. But it is far better than risking loss of life and limb.

As for the events leading up to the collision, what has been revealed so far is troubling on at least one count.

On the morning of Nov 15, operator SMRT was already aware that a train had developed signalling problems - which was why it was ordered to be driven in restricted manual mode, meaning the driver taking the controls, with the speed capped at 18kmh.

However, the train behind was allowed to remain in automatic mode (even if its speed followed the same cap). As it turned out, this second train, unable to detect the location of the first train, ran into it at Joo Koon.

It took it a relatively long 10 seconds to make contact, but the driver failed to react as he was not expecting this.

There must be another lesson in there somewhere.

Signalling system firm Thales apologises for Joo Koon train collision; assures commuters that its system is safe

** LTA completes probe into Joo Koon train collision

Simulation facility to test new East-West Line (EWL) MRT signalling system
French firm Thales to set up facility for East-West Line's system before it is rolled out
By Adrian Lim, Transport Correspondent, The Straits Times, 19 Dec 2017

A simulation facility will be built for the East-West Line's (EWL) new signalling system to undergo extra tests before it is rolled out, in a move to beef up safety and not disrupt train services.

The facility will be set up by French firm Thales, which aims to deliver the new signalling system for the EWL by next June.

It is the first of its kind testing facility outside Toronto and Paris, where the firm is based.

The location of the facility - which is being established following a collision on the EWL last month - will be decided in due course, the Land Transport Authority (LTA) said yesterday, when it released its findings on the Nov 15 accident.

The collision, the first of its kind for Thales, was caused by compatibility issues between the new system to be installed, and an older system now running on the EWL.

The LTA said the findings of its investigation were consistent with what it discovered in its initial inquiry: that there was a software logic issue with the new communications-based train control (CBTC) system "which was not configured to cater for the failure conditions that occurred on Nov 15".

LTA said its findings were corroborated by a report submitted by Thales, which has taken full responsibility for the accident.

Further tests and analysis were also conducted by LTA, Thales and operator SMRT. The collision, on the westbound tracks at Joo Koon MRT station, left 36 commuters and 2 SMRT staff injured.

LTA said Thales' simulation facility will strengthen testing processes for both the EWL and North-South Line, which is already running on the CBTC system. The facility will also allow additional tests "tailored to the environmental and infrastructural conditions of the rail network in Singapore" to be performed.

LTA added that "the facility will also enhance our ability to test solutions for CBTC issues in a controlled setting without affecting train services".

The facility will be established in two phases: the first will be done by the first half of next year, before the CBTC is fully launched on the EWL.

The second, to be ready by the end of next year, will further strengthen the centre's testing capabilities.

In its report, the LTA said a slew of remedial actions have been taken following the accident. These include separating the sections of the EWL that run on the CBTC and the old fixed-block system since Nov 20, as a precautionary measure until June.

At the time of the accident, trains had to switch from the new system at Tuas West Extension to the old system on the rest of the EWL.

LTA said Thales is fixing the software logic of the CBTC system and has completed modification works for a circuit at a track point, which was incompatible with the CBTC.

These glitches had led to the Nov 15 accident.

Assistant Professor Andrew Ng, from the Singapore Institute of Technology's engineering cluster, said the simulation facility will improve the robustness of the new CBTC system. "It will allow any unforeseen events to be predicted, and measures to be implemented before problems happen," he added.

He said various scenarios can be tested, like the re-scheduling of trains' timetables due to a delay. "This will optimise the movements and launching of trains," he added.

While the simulations can be done overseas, he said there is value in having the facility here, as the expertise of local rail engineers can be built up.

LTA may act against those linked to Joo Koon train collision
By Adrian Lim, Transport Correspondent, The Straits Times, 19 Dec 2017

Action could still be taken against the parties who were involved in a collision of two MRT trains on Nov 15, the Land Transport Authority (LTA) said yesterday, in response to queries from The Straits Times.

The LTA said it "reserves the right" to take appropriate action, without stating what that might be.

The French company building the new signalling system for the East-West Line has taken full responsibility for the collision, which left 38 people injured and caused train delays affecting nearly 13,000 commuters. It was caused by compatibility issues between the existing signalling system and the new communications-based train control (CBTC) system which Thales is installing for the line.

An LTA spokesman said: "Thales has acknowledged its responsibility for this incident, and has apologised to the public. It has also committed to establishing a CBTC simulation facility in Singapore, including stationing engineers to support the set-up phase."

The facility, whose location was not stated by the LTA, will support additional testing of Thales' signalling system.

In its investigation report released yesterday, the LTA said several remedial actions had been taken following the collision.

On Nov 16, Thales completed the circuit modification works on a track point involved in the accident the previous day. On Nov 15, this track point near Clementi MRT station, not yet fully modified for compatibility with the CBTC system, removed a protective "bubble" when a train travelled past it.

The bubble acts as an invisible barrier in the CBTC system, preventing trains from knocking into each other. When the bubble was removed, the train became invisible to the one pulling up behind it at Joo Koon MRT station, causing the collision. The bubble that was disabled was actually a backup that had been applied after a first bubble was inadvertently removed by a glitch in the on-board CBTC equipment of the affected train.

Thales is also modifying the software logic of the CBTC system to prevent this backup bubble from being removed, the LTA said.

*** Parliament: Train driver did not have time to prevent Joo Koon collision, says Khaw Boon Wan
No time to react as emergency braking situation not expected
By Christopher Tan, Senior Transport Correspondent, The Straits Times, 11 Jan 2018

The driver of an MRT train which ran into a stationary train at Joo Koon station on Nov 15 could not have reacted in time to apply the emergency brakes.

Transport Minister Khaw Boon Wan told Parliament yesterday that this was because the line's operating control centre did not expect the train's second protective "bubble" - which ensures a safe distance between trains - could be disabled.

The first protective bubble had collapsed earlier, and it was moving with the second bubble in place.

Because the operator did not expect this, it allowed the train to proceed in automatic mode. And since the train was in automatic mode - which does not require driver input - the driver did not expect a situation in which emergency braking was required. Until it was too late.

Mr Khaw illustrated this with an anecdote of a fatal accident involving a personal mobility device.

He said a friend, who was a corporate lawyer, called him "frantically" one day to tell him that he had knocked down an e-scooter rider at a pedestrian crossing. The rider later died in hospital.

Mr Khaw said his friend did not see anyone at the crossing at the time, and had slowed down but did not stop. But "the next second, he saw somebody on an e-scooter flung onto his windscreen".

The minster said this was the same situation which the train driver faced.

"At that moment, are you able to respond in time? Thirty-six metres, yes, is not a short distance but the speed was 18kmh," he said, referring to the distance between the two trains and the speed of the second one when it collided with the stationary one.

In his explanation, Mr Khaw noted that the driver also had to switch to manual mode before he could apply emergency brakes. "Based on logs and reviews, the train driver could not react in time."

Workers' Party Non-Constituency MP Dennis Tan Lip Fong asked the minister to clarify if indeed a train's emergency brakes would work only in manual mode.

Mr Khaw said: "I'm not perfectly sure, but I'll check."

He later told the House that emergency brakes can be applied even when trains are in automatic mode.

Mr Khaw pointed out that having the Tuas West Extension running on a new signalling system while the rest of the East-West Line was operating on the old system contributed to the problem.

The two lines have since been truncated between Joo Koon and Gul Circle. Commuters have to alight at either stop and take a free shuttle bus to the other in order to continue their journey.

Mr Khaw said this arrangement will continue till the middle of the year, when the entire East-West Line has converted to the new signalling system.

Sections of the line will have shorter operating hours on Fridays and Saturdays, and no service on Sundays, to speed up the signalling upgrade.

Joint Statement by the Land Transport Authority (LTA) & SMRT - Update on Joo Koon train incident -15 Nov 2017
Update on Train Incident at Joo Koon Station -15 Nov 2017
MRT tunnel flooding: SMRT maintenance team failed us, says Khaw Boon Wan; Suspected falsification of records, pumps at Bishan not maintained for almost a year
MRT tunnel flooding incident: Khaw Boon Wan's ministerial statement in Parliament on 7 November 2017
Joint News Release by the Land Transport Authority (LTA) & SMRT - Investigation Findings on Train Collision at Joo Koon MRT Station & Shorter Operating Hours along NSEWL in December -21 Nov 2017
LTA: Completion of Detailed Investigation into the Train Collision at Joo Koon MRT Station -18 Dec 2017
Oral Reply by Minister for Transport Khaw Boon Wan to Parliamentary Question on Joo Koon Collision -10 Jan 2018

MRT incidents like Joo Koon collision should not have happened; we must put things right: Prime Minister Lee Hsien Loong