SINGAPORE: Seventeen East-West Line (EWL) MRT stations and two North-South Line (NSL) MRT stations will be fully closed on Dec 10 and Dec 17 to allow for extended engineering hours, train operator SMRT and the Land Transport Authority (LTA) said in a joint statement on Tuesday (Nov 21).
In addition, from Dec 8 to Dec 31, the 17 EWL stations from Tiong Bahru to Tuas Link as well as Bukit Batok and Bukit Gombak stations on the NSL will close earlier on Fridays and Saturdays (at 11pm) and open later on Saturdays and Sundays (at 8am), according to the statement.
The shorter operating hours will double engineering and track access time for engineers to "accelerate" re-signalling works on the EWL, LTA and SMRT said.
Bukit Batok and Bukit Gombak are affected as engineering works will extend to Jurong East MRT station, a heavily used intersection of the NSL and EWL, they added.
With extended engineering hours from December, the completion of re-signalling works on the EWL will be "significantly accelerated" from the end of 2018 to June 2018, authorities added. Works for the NSL are on track to be completed by next month.
In the first half of 2018, reduced train service hours will also be introduced along other stretches of the NSEWL, said LTA and SMRT. Parallel shuttle buses will be provided along affected MRT stations during affected hours and fares will follow the rail fare structure.
The move comes after a software glitch in the EWL signalling system caused two trains to collide at Joo Koon MRT station last week, injuring 38 people.
ADDITIONAL ENGINEERING HOURS ‘VERY PRECIOUS’: LTA
Two signalling systems actively operate on the EWL - the new Communications-Based Train Control (CBTC) system, which is active between Tuas Link and Pioneer MRT stations, and the legacy signalling system, which controls train movements between Pioneer and Pasir Ris stations.
The revised engineering schedule announced on Tuesday will accelerate re-signalling works on the EWL "so that train services on the entire line, including TWE (Tuas West Extension), can run seamlessly on the new CBTC system", the joint statement said.
This will also provide more time for other renewal projects and maintenance works to "improve overall reliability" on the NSEWL.
Speaking at a joint LTA-SMRT media briefing, Mr Ngien Hoon Ping, LTA's chief executive, said that more details would be announced at a later date and that the authority would work with public transport operators to ensure there are alternatives for commuters who need to travel along the stretches affected.
"The additional engineering hours are very precious to LTA, SMRT and (signalling contractor) Thales," said Mr Ngien. "This will substantially accelerate the implementation of the new signalling system for the EWL and provide additional maintenance hours for the entire NSEWL network."
He added that December was chosen to “quickly execute these plans” as it is a period when many Singaporeans are not in the country.
However, Mr Ngien stressed that there remains “quite a lot of work to be done”.
“If we do want to accelerate the completion of the CBTC system on the EWL, then from January onwards all the way to June, we will continue to look at additional engineering hours for SMRT and Thales to work on,” he said. “And then we can have a full, proper system come end of June.”
He added that the authorities are not ruling out full-day closures in future, and that those closures are likely to take place on Sundays.
“Preliminarily, we are already working on some plans, there will be other segments along the EWL that we will be looking at ... in terms of having to close them earlier so that we can allow for SMRT to complete their maintenance work,” he said.
“We will have people on the ground to monitor how the response and reactions will be, but it’s something that we have to do,” he added. “Because if we do not take action on this, then this re-signalling project will be extended all the way to the end of the year.”
"PROTECTIVE BUBBLE" FEATURE DISABLED BY "ABNORMAL CONDITION" ON TRAIN EQUIPMENT
LTA, SMRT and Thales also confirmed that the Joo Koon collision had been caused by an "unexpected disabling of a protective feature" on the train that was hit.
The train was launched at 5.38am from Ulu Pandan Depot to serve commuters towards Pasir Ris and then to turn back to Tuas Link, authorities said.
Investigation findings indicated that an "abnormal condition on a train-borne CBTC signalling equipment" disabled a feature designed to apply a protective "bubble" around the affected train to ensure safe distances between trains, said authorities.
When this happens, the CBTC system should immediately apply a second protective "bubble" to replace the first one, authorities added.
However, this second bubble was "unexpectedly disabled" when the train passed by a "trackside device" at Clementi which had 'yet to be modified for compatibility" with the new CBTC system.
When the train arrived at Pioneer MRT station where it transitioned to the new CBTC system on the TWE, the train captain "correctly detected" the abnormal condition and reported it to the Operations Control Centre, authorities added.
The train was directed to Joo Koon MRT station for passengers to alight.
When it stopped at the station, platform screen doors were manually opened and a "closed track" protection was automatically activated to prevent other trains from entering or leaving the platform.
When this protection was lifted to allow the first train to leave the station, the second train "started to move forward automatically" as it could not sense any protective bubbles around the first train, SMRT and LTA said, resulting in the collision.
There was no human error in this case, said Alvin Kek, SMRT Trains’ senior vice president for rail operations on the North-South and East-West lines.