A power fault triggered an unprecedented breakdown of train services along three MRT lines and one LRT line last night, disrupting the journeys of thousands of commuters near the end of the evening peak.
The trip, which occurred at 7.53pm, also led to blackouts and a loss of air-conditioning at all affected stations. They were without power except for emergency lighting.
Train services were unavailable for between 30 minutes and two hours, and free bus shuttle services were deployed.
Operator SMRT said it traced the fault to a "power dip" at the Buona Vista power intake station, which takes power from the power grid to run sections of the rail network. This caused a power trip, it said.
There are five power intake stations along the North-South and East-West Lines (NSEWL) and the Circle Line (CCL). Checks with SingPower revealed that the power dip was not a supply issue.
Along the East-West Line, service was shut down in both directions from Joo Koon to Buona Vista, with stations up to Bugis affected at one stage. Along the North-South Line (NSL), stations from Jurong East to Kranji were hit, while on the CCL, stations stretching from Caldecott to HarbourFront were affected.
Four trains stalled between stations along the Bukit Panjang LRT Line, and 150 passengers on board were safely evacuated, SMRT said.
It remains unclear why the power fault affected the CCL and LRT line, as they are not connected to the other rail lines, unlike the NSEWL. SMRT is investigating the cause.
The major disruption came hours after SMRT released findings of an investigation into how two of its staff were killed by a train along the tracks near Pasir Ris station last month.
The operator said failure to follow safety measures before allowing a work team onto the train tracks had "directly" caused the accident. These safety lapses included a failure to provide early warning to the work team.
While last night's power trip affected mainly stations in the west, it was reminiscent of the massive breakdown on July 7 last year which crippled the entire NSEWL for hours.
According to SMRT, last night's services on the NSEWL were disrupted for about 30 minutes till 8.23pm, and for about an hour on the CCL. Trains began running only more than two hours later on the LRT line, close to 10pm.
SMRT deployed shuttle buses to ferry commuters, and said free bus services were activated at 8.15pm. All affected commuters can get a refund in the next 14 days, it said.
Some commuters had trouble locating the free bus services, which remained patchy. At Choa Chu Kang station, housewife Melanie Lee, 55, and her family spent an hour looking for the shuttle bus from 9pm to 10pm, to get home to Fajar.
"First we went to one side, then we went to another but (there was) still no bus," she said. "There's nobody guiding us... How can they waste our time like this?"
SMRT has been trying to improve reliability on the ageing NSEWL through multiple infrastructure renewal projects, including replacing the power-supplying third rail and upgrading the signalling system.
The NSL had gone for 100 days without a major disruption, but the streak ended on April 21.
•Additional reporting by Christopher Tan, Olivia Ho and Ng Keng Gene
All stations without power except for emergency lights.
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