A signalling fault on the North- South Line yesterday caused trains to slow down over a period of three hours, and the Land Transport Authority (LTA) and SMRT warned of more potential delays as tests intensify for the line's new signalling system.
The delays yesterday and on Thursday were caused by two unrelated faults uncovered during system-level performance checks on the line's new signalling system, the LTA and SMRT said in a joint statement yesterday.
As testing continues and intensifies, there may be more delays until the new signalling system - supplied by French transport system giant Thales - stabilises.
The fault on Thursday was caused by a glitch in the computer server used to manage train schedules, while yesterday's delays were due to a fault in signalling equipment known as the Movement Authority Unit (MAU).
The MAU fault, registered at around 4.45pm, resulted in slower train movement between Kranji and Admiralty stations. Service recovery took some time as engineers needed to troubleshoot and replace components. Service progressively resumed just before 8pm.
SMRT first notified commuters of yesterday's delays on its Twitter page at 5.05pm, asking travellers to add 15 minutes of travel time between Marina South Pier and Jurong East, in both directions, due to "new signalling system checks".
It later updated its advisory, asking commuters to add 30 minutes travel time between Yew Tee and Yishun, in both directions, and said that trains were travelling at a slower speed. Free regular bus and bus-bridging services were available at certain stations.
More noise barriers
The Land Transport Authority (LTA) yesterday called for a tender to install an additional 10km of railway noise barriers at 20 new locations along the North-South and East-West lines.
The affected tracks stretch from Pasir Ris to Tanah Merah MRT stations, and Jurong East to Bishan stations. Barriers will also be erected between Redhill and Queenstown stations, between Commonwealth and Buona Vista stations, and between Clementi and Jurong East stations.
This is the second phase of the railway noise-barrier programme. The LTA aims to award the tender by the third quarter of this year.
When completed by 2020, the barriers are expected to reduce sound levels by 5 to 10 decibels, the LTA said.
Chew Hui Min
At Yishun, commuters were asked to get off, and were handed pamphlets by staff on the alternative modes of transport available.
Mr Lazaro, a 45-year-old IT specialist, told The Straits Times the delays had affected his plans for the evening. He said his journey, which had started at Novena, was delayed by close to 21/2 hours.
A 65-year-old woman, who gave her name only as Madam Ng, said she had been late for work every day this week because of train delays.
The upgraded signalling system had been unveiled as one of the key projects to renew the 30-year-old North-South Line, and testing began in late March.
LTA and SMRT said signalling trials are part and parcel of new signalling systems and are carried out to help operators identify and resolve teething problems.
They said: "We are very sorry for the inconvenience caused and we seek the patience of commuters."
•Additional reporting by Senior Transport Correspondent Christopher Tan