NSL signalling tests move to next phase: Weekday trials
Mr Chua Chong Kheng, deputy chief executive for infrastructure and development with the Land Transport Authority (LTA), said that new signalling system will enter one of its final stages of testing on the North-South Line from next week. Photo: Jason Quah/TODAY
SINGAPORE — The new signalling system that is expected to shorten waiting times on the North-South Line will enter another stage of testing from next week.
This time, it would be put through its paces on weekdays, and the tests will involve the line’s full fleet of 124 trains.
According to Mr Chua Chong Kheng, deputy chief executive for infrastructure and development with the Land Transport Authority (LTA), the upcoming trials would be the “real test” since they would also involve a larger number of commuters.
The trials have been expanded progressively, starting from March when the signalling system was tested during the last hour of weekday services to it being tested on Sundays since last month, with 55 trains in the drill.
The Sunday tests — set to last two months from April 16 — will continue, and the system will be tested on one or more weekdays during the week.
Describing this as a “major step forward”, Mr Chua said that “full testing” would be done “in a very cautious manner”, anticipating that there could be some delays as rail operator SMRT works through teething issues.
For example, with more commuters, problems would have to be resolved in the shortest possible time, as crowd build-up would be “quite significant” and problems that crop up during peak-hour would be “very disruptive compared with a Sunday”.
Should such incidents happen, SMRT will deploy more ground crew at the stations to help and guide commuters.
During earlier trials, there were times when the platform screen doors failed to open and trains overran stations.
Mr Chua explained that, in rainy conditions, stopping trains accurately at above-ground stations was a challenge — especially with the system having to work with “four different fleets of trains” on the North-South Line.
In wet conditions, there are “adhesion” issues and wheels “get locked and slide” at times, causing trains to misalign with the platform screen doors.
These could cause delays as time is needed for trains to return to position and for the doors to open. “We seek commuters’ understanding … that there could be some delays and we’ll try to resolve these as quickly as possible as they happen,” he added.
However, such problems have improved over the weeks of testing, Mr Chua said, and SMRT’s contractor for the system, Thales, has put in place solutions.
Among other things, the LTA has been working with SMRT and Thales to make software adjustments, in an effort to fine-tune the “braking profile” of trains to slow them down as they enter stations, particularly in wet weather.
In the interim, the LTA has also been looking at a speed restriction, especially at stations with “steep gradients” that can cause trains to enter stations “very fast”.
While he did not specify a working schedule, Mr Chua said that the signalling system would be rolled out sometime this year when the LTA is “comfortable that the system is performing as expected” and most of the issues have been resolved.
The new system was originally slated to run by the end of last year, but the LTA previously said it needed more testing to ensure its reliability.
Allowing trains to run at shorter intervals, the system can raise peak-hour capacity by up to 20 per cent. During peak hours, commuters can expect to wait up to 100 seconds, instead of the present 120 seconds.
Armed with features such as critical components that are duplicated as back-up, the new system provides better support in the event of a signal fault, and is thus expected to improve rail reliability.
After its roll-out, Mr Chua said that it would take about “four to six months” for the system to stabilise. “Commuters can then reap the full benefits of the system eventually,” he added.
