A malfunction in the water pumping system was the cause of flooding in the MRT tunnels and subsequent disruption of North-South Line train services for more than 20 hours over the weekend, preliminary investigations have found.
The Land Transport Authority (LTA) said in a statement yesterday that the pumps failed to siphon off rainwater, which seeped into the tunnel through the portal opening near Bishan station after Saturday's torrential rain. Water levels rose to over 30cm in the tunnel between Bishan and Braddell stations, The Straits Times understands.
As a result, train services between Ang Mo Kio and Marina South Pier were grounded on Saturday night. They were partially restored by 9.30pm, but services between Ang Mo Kio and Newton remained down yesterday morning. Full service resumed only at 1.50pm yesterday.
More than 40 buses from SMRT and SBS Transit were deployed for bridging services, while officers from the Singapore Civil Defence Force, PUB, LTA and SMRT worked overnight to clear water from the tunnel and restore train services.
Train operator SMRT said on Facebook yesterday it was "very sorry for the inconvenience commuters had to bear" in one of the worst train disruptions here since 2011.
Detailed investigations into the cause of the incident are ongoing, said LTA.
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