Mysterious signal fault hits Circle Line again
Published 6 hours ago
Disruption affects thousands of commuters during morning crush
Christopher Tan
Senior Transport Correspondent
The mysterious signal interference which interrupted service on the Circle Line MRT two months ago is back. Thousands of commuters were affected during the morning crush yesterday when an “intermittent signal fault” persisted for three hours from around 7.30am.
At one point, service ground to a halt for more than an hour in the northern stretch of the line, affecting five stations between Botanic Gardens and Serangoon. On other parts, journeys were delayed by 20 to 30 minutes up to past 10am.
The disruption had a ripple effect as stranded commuters took to taxis and private transport, adding to peak-hour traffic on the road.
Motorist Chester Chong said he took an hour and 20 minutes to get from Teban Gardens to Bartley, a journey which usually takes 45 minutes or less.
“I was stuck on the PIE (Pan-Island Expressway) for 45 to 50 minutes,” the 31-year-old sales consultant said. “When I reached the Braddell flyover, I could see a huge jam in the other direction.”
SMRT said that preliminary findings revealed a communications glitch similar to the one which disrupted service on the line for a week in late August.
The first incident was traced to an unknown signal interference which disappeared as mysteriously as it appeared - before the source could be established.
In a joint statement yesterday, SMRT and the Land Transport Authority said they had arranged with the Infocomm Media Development Authority and mobile network operators “to suspend telecommunication signals along stretches of the line for short periods of time to assist in investigations”. This is to establish whether telco signals are behind the interference.
They also said the driverless Circle Line trains “will be manned during evening peak hours”.
SIM University senior lecturer Park Byung Joon said: “They have to find the source of this interference. The system is not a living organism. It won’t heal itself. So unless they find the fault and fix it, it will remain.”
Meanwhile, many commuters reached their destinations far later than usual.
IT consultant Davis Li, 32, was stuck in a train for an hour and 45 minutes when it stalled between Caldecott and Marymount stations.
“I got on at 8.15am, and the train started to move again only at 10am,” he said.
He reached his workplace in Bishan at 10.30am - 90 minutes late.
Undergraduate Denise Tan, 21, said she was late for class despite spending $33 on a cab which she managed to secure after 20 minutes. She usually takes the train from Bartley to Kent Ridge station.
continue reading here :
http://www.straitstimes.com/singapor...cle-line-again
Commuters no need to complain just go and sue the SMRT .
Persistent signal issue worrying and a bad sign: Experts
Authorities shutting down telco services from time to time to try and find source of interference
By Kenneth Cheng
Published: 4:00 AM, November 3, 2016
Updated: 11:14 AM, November 3, 2016
SINGAPORE — While the authorities and rail operator SMRT have announced steps to try to solve the bewildering signal fault on the Circle Line (CCL) — including manning the trains during evening peak hours yesterday — these are not permanent solutions and nipping the interference at the source is still key, experts said yesterday.
The intermittent signal interference that triggered delays on the 30-station line from Aug 29 to Sept 2 returned during the morning rush-hour yesterday, crippling services at six stations.
The fact that the source of the faults continues to elude the authorities and SMRT is “a pretty bad sign”, said Professor Lim Teng Joon, a wireless-communications expert at the National University of Singapore.
Singapore Institute of Technology railway signalling control and communications lecturer Andrew Ng said the fact that the problem has persisted for so long suggested that “a combination of sources” could be behind the interferences.
If this is so, Prof Lim said it would be “a very sophisticated attack” and could point to transmitters being placed at several points along the line.
Detecting the source is nevertheless “extremely difficult”, he acknowledged.
Since electromagnetic waves generated by various sources are bouncing off all the walls, “even if you could somehow detect (their) arrival, it doesn’t indicate the direction of the source of the signals”, Prof Lim said, adding that the signals may not be on long enough to be detected.
For now, the only fail-safe solution is to drive the trains manually on the driverless CCL, the two experts said.
Doing so obviates the need for the system to rely on electronic signalling, which typically controls a train’s speed and the distance between trains, Prof Lim said.
Agreeing, Assistant Professor Ng noted that the current set-up means that the CCL is heavily reliant on wireless communications between trains and tracks.
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Signal glitch on Circle Line continues, delays expected on Thursday evening
Published 58 min ago
Christopher Tan
Senior Transport Correspondent
SINGAPORE - Rail operator SMRT warned that there may be delays on the Circle Line (CCL) on Thursday evening (Nov 3) because of an unresolved signal interference.
It tweeted at 6.07pm, saying: “Due to intermittent signal interference, CCL trains may experience delays.
“For safety, CCL trains are manned this evening. We are sorry.”
The unknown interference resurfaced on Wednesday morning (Nov 2), after a two-month reprieve. It first appeared in late-August, and crippled Circle Line service for about a week. It disappeared as suddenly and as mysteriously as it appeared, and engineers were not able to trace its source.
SMRT suspects it may have to do with telecommunications cables in the tunnels, but despite having roped in the Infocomm Media Development Authority and mobile network operators to help, it could not resolve the issue.
The stray signal interferes with the wireless signal communication between the trains and the tracks, causing the trains to apply emergency braking.
continue reading here :
http://www.straitstimes.com/singapor...ursday-evening
For safety reasons please do not take CCL . Boycott SMRT .
Circle Line signal woes: What we know so far
What is the issue plaguing the rail network run by SMRT, and what are SMRT and LTA doing to address the root issue of the signalling woes said to be causing the service disruptions?
Posted 03 Nov 2016 17:15
Updated 03 Nov 2016 19:23
SINGAPORE: Commuters in Singapore experienced another service disruption on the Circle Line on Wednesday (Nov 2), with operator SMRT and the Land Transport Authority (LTA) stating that “intermittent signal interference” was the cause of the three-hour long episode.
In a tweet on Thursday, SMRT said due to intermittent signal interference, Circle Line trains may experience delays. “For safety, CCL trains are manned this evening. We are sorry,” it said.
Services were disrupted between Botanic Gardens and Serangoon stations, after one train stalled in the direction of Dhoby Ghaut. Other parts of the Circle Line were also hit by delays after trains travelled at a slower speed due to the signalling issue.
LTA and SMRT indicated in their statement on Wednesday that the nature of the faults could be similar to those that plagued the line earlier in September, when train services were repeatedly delayed on five consecutive days due to signalling issues.
So what is the issue at hand, and what are LTA and SMRT doing to get to the root of the issue and prevent future such occurrences?
WHAT IS THE RAIL SYSTEM USED?
LTA awarded the contract to French manufacturer Alstom in 2000 to have its Alstom Metropolis C830 trains ply the Circle Line. For its signalling requirements, the trains and controls use the Urbalis communication-based train control (CBTC) rolling stock, which is similar to those used in the North East Line (NEL), but powered by a third rail instead of an overhead power source.
According to an Alstom, the Urbalis CBTC “gives operators precise control in the movement of their trains, allowing more trains to run on the line at higher frequencies and speeds in total safety – with or without drivers”.
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Quote:
Originally Posted by
SiaSuay
I bet they will form a committee to investigate what happen. Such a small area still cannot solve the problem ? What the LTA & SMRT engineers are doing ? Again let me give some suggestion maybe they should change the receiving signal frequency of the train . Or they should just put a train driver in charge . Are those driverless trains really that safe to travel on ?
Looks like somebody is reading your post .
Mobile service suspended on Circle Line on Thursday night
Published 1 hour ago
Updated 23 min ago
Chew Hui Min
SINGAPORE - Mobile operators and the Land Transport Authority said that mobile service along the Circle Line will be suspended until late on Thursday (Nov 3) night.
“On instructions from the authorities, mobile network equipment along the Circle Line will be suspended until 10.30pm,” M1 announced on Facebook.
“During this period, you will not be able to make calls, send messages, or access the Internet.”
Starhub said, also on Facebook: “We have been instructed to turn off mobile services in the Circle Line. During this period, you will not be able to make calls, send SMS or access the internet when travelling on Circle Line.”
Singtel’s update also confirmed that service will be suspended until 10.30pm.
“Due to ongoing checks on Circle Line signalling system by LTA, mobile customers will not be able to receive mobile signals at all CCL stations from Harbourfront to Bayfront from now to 10.30pm tonight,” it said in a Facebook post.
continue reading here :
http://www.straitstimes.com/singapor...on-thursday-m1
Why can’t they shut down the entire CCL to do a thorough check in the tunnel ?
Mobile service on Circle Line resumes at 10.30pm on Thursday night after suspension
Published 2 hours ago
Updated 21 min ago
Chew Hui Min
SINGAPORE - Mobile service along the Circle Line resumed at about 10.30pm on Thursday (Nov 3) after a suspension of more than an hour.
The suspension was to facilitate tests for the source of a signal interference which disrupted train service on Wednesday.
“Telco signals will progressively resume along Circle Line,” SMRT said in a tweet.
M1 also announced on on Facebook at 10.32pm that mobile service had resumed on the line.
Mobile operators and the Land Transport Authority said at about 8.45pm that mobile service along the Circle Line will be suspended on Thursday night.
“On instructions from the authorities, mobile network equipment along the Circle Line will be suspended until 10.30pm,” M1 announced on Facebook.
“During this period, you will not be able to make calls, send messages, or access the Internet.”
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Mobile services on Circle Line suspended on Friday morning as commuters told to expect delays
Published 6 min ago
Derek Wong
SINGAPORE - Mobile service on the Circle Line (CCL) was temporarily switched off until 9am on Friday (Nov 4) morning, the three telcos said.
SMRT had first announced at 6.43am that CCL trains might experience delays due to signal interference and that CCL trains were manned on Friday morning.
It then tweeted at 7.04am that commuters along the CCL will experience temporary suspension of mobile services.
Telco companies Singtel, Starhub and M1 also announced on Friday morning that their mobile services on the CCL would be temporarily suspended until 9am.
The suspension comes after an earlier halt was carried out on the CCL on Thursday night for more than an hour until about 10.30pm.
Telcos said that mobile service along the Circle Line would be suspended on Thursday (Nov 3) night.
The suspension was also to facilitate tests for the source of a signal interference which disrupted train service on Wednesday.
A mysterious signal interference had resurfaced on Wednesday morning, interrupting train service on the Circle Line for three hours during peak hour.
Service ground to a halt for more than an hour at five stations between Botanic Gardens and Serangoon.
The signal interference first occurred in late August, disrupting service on the Circle Line for a week.
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http://www.straitstimes.com/singapor...muters-told-to
Still cannot solve the problem ?
Unexpected shutdown of telco services along Circle Line upsets commuters
Commuters on CCL were not able to make calls, send messages, or access the Internet during the suspension
Published: 6:21 PM, November 3, 2016
Updated: 8:41 AM, November 4, 2016
SINGAPORE — With nary a warning, mobile signals were shut down for at least two hours throughout the entire Circle Line (CCL) on Thursday (Nov 3) night.
The unprecedented move, which upset thousands of commuters, was ordered by the Land Transport Authority (LTA) as it tries to flush out the culprit behind the recent signal interferences that caused several disruptions since August.
Commuters fumed, saying an SMS alert could have been sent out moments before the shutdown, even if tests had to run promptly.
A 53-year-old IT professional who wanted to be known only as Ms Tan said: “When my line got cut suddenly, I felt quite helpless. I didn’t know what was happening.”
Ms Lily Toh, 62, a salesperson, added: “They didn’t inform us beforehand, so I thought I was experiencing a billing issue when my line got cut suddenly. I would appreciate it if they could send us a message to inform us before cutting the signal in future.”
Asked about such sentiments, the SMRT and LTA pointed to their statement on Wednesday that said suspensions of mobile signals could be carried out should signal interferences recur, and that announcements would be made in trains and stations.
Ms Tan, however, felt that the announcements were “not clear enough” and she did not know it was related to tests to tackle the train signal faults.
Professor Lim Teng Joon, a wireless-communications expert at the National University of Singapore, said it would have been better if commuters had been given advance notice of the mobile services shutdown.
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Whole-day shutdown the latest twist in CCL mystery signal hunt
By Kenneth Cheng
Published: 4:00 AM, November 5, 2016
SINGAPORE — The hunt for the source of interfering signals that have repeatedly disrupted train services on the Circle Line (CCL) in recent months was ratcheted up a notch yesterday, with the authorities taking the unprecedented step of ordering a full-day suspension of mobile services through all 30 stations.
Experts TODAY spoke to generally did not want to speculate on why mobile services had to be suspended across the entire line — the mobile network will be restored progressively from 11am today.
But Professor Lim Teng Joon, a wireless-communications expert at the National University of Singapore said: “The fact is we don’t have enough information … but (based on the scale of the shutdown) it sounds to me that they’re still quite far from the answer unless they have some kind of strategy that they’re not telling us about.”
The first mobile-service suspension on the CCL was in September and lasted for two hours at four stations. On the second and most recent time — on Thursday, a day after train delays hit various locations on the CCL — it extended to the whole line, but for about two hours.
Yesterday’s shutdown was to have lasted two hours or so, according to the first announcement just after 7am. SMRT warned of delays on the CCL owing to the recurring signal fault but trains appeared to run smoothly at several stations TODAY visited.
Later in the morning, however, the suspension of mobile services was extended to the whole day, with the Land Transport Authority (LTA) citing “ongoing tests”. An Infocomm Media Development Authority spokesperson said it asked Singtel, StarHub and M1 to kill their networks on the CCL yesterday “to allow the LTA and its contractors to undertake a rigorous process of elimination so that all possible causes can be isolated and investigated fully”.
continue reading here :
http://www.todayonline.com/singapore...-signal-hunt-0
Commuters please don’t complain that you cannot use your mobile devices . It is not the Telcos’ fault . You should complain to SMRT & LTA instead .