Train services on the Bukit Panjang LRT were fully restored yesterday afternoon, after going off-track for almost 24 hours.
At about 1pm, services running in a clockwise direction from Senja to Petir stations on the 14-station line resumed. At around 5.30pm, services in the opposite direction restarted.
Operator SMRT is giving commuters free rides on the Bukit Panjang LRT from the time service resumed till noon today.
During the disruption, commuters were given free rides on shuttle buses running parallel to the train route, as well as on regular buses calling at station bus stops.
Still, some complained about the inconvenience.
One of them, Ms Jessica Tan, 44, a part-time trainee teacher, took urgent leave to get her daughter to school on time.
The suspension of LRT service started on Monday evening after a fire broke out at an electrical room in Senja station at 5.45pm.
Preliminary investigations indicate that a tie-breaker overheated and caught fire. A tie-breaker is an electrical circuit breaker that connects two sectors of the power rail, and is used to supply power to the train.
A picture of the charred electrical box and other components surrounding the device was posted on Facebook by Transport Minister Lui Tuck Yew, who visited the station yesterday morning.
He wrote that the device had just been installed on Sunday to replace one that had "arcing problems". "Arcing" is an electrical discharge that jumps across a gap in a connection.
As investigations continue into the causes of the fire, The Straits Times understands that it could have been started by a faulty circuit breaker. The burnt component has been sent to a laboratory for study. One theory being explored is that the electrical system could have been overtaxed as more trains were added to the system, and the newer trains deployed are heavier and draw more power. But this is still being studied, sources said.
The Straits Times understands that SMRT needs time to source the replacement parts. Meanwhile, it will bypass the burnt circuit breaker.
Professor Liew Ah Choy from the National University of Singapore's electrical and computer engineering department said that, in general, tie-breakers are like fuses and serve the function of "opening" or "tripping" when there is an abnormality in power. "By bypassing it, you lose the protective element in that circuit."
SMRT said 20 train cars were tested on the system following the bypass to ensure it ran safely.
Mr Lui said on Facebook that the "overall health" of the LRT system will be reviewed by a joint team from the Land Transport Authority and SMRT.
Additional reporting by Olivia Ho, Isaac Neo and Rachel Tan
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