Full train services on the North-South Line (NSL) resumed at 1.50pm, following overnight recovery works to clear water accumulated in the tunnels after a torrential downpour.
2. Preliminary investigations indicate that water had entered the tunnels through the portal opening near Bishan MRT station, where aboveground rail tracks transit underground. Under normal circumstances, rainwater runoff accumulated in the adjacent storm water sump pit would have been siphoned off by a system of pumps. Yesterday, the water pumping system malfunctioned, resulting in rainwater overflowing from the storm water sump pit into the tunnel opening and accumulating at the lowest point of the tunnel, between Bishan and Braddell stations. As a safety measure, SMRT immediately deactivated the trackside power supply. The pump system has since been repaired. Detailed investigations into the cause of this incident are ongoing.
3. Since yesterday evening, officers from the Singapore Civil Defence Force and PUB have been working through the night alongside LTA and SMRT officers to clear the water, with SBS Transit also on standby to support the recovery efforts. Affected trackside equipment was subsequently inspected, cleaned, replaced and tested before passenger services resumed. Checks have also been conducted on other tunnel portal pump systems located throughout the North-South and East-West Lines (NSEWL).
4. During the service disruption, free regular bus and bus bridging services were activated promptly for affected commuters. More than 40 buses from SMRT and SBS Transit were deployed to provide bus bridging services. Information was also made available at stations and updates provided on the SMRT website and Facebook; LTA and SMRT Twitter accounts; LTA Traffic News and MyTransport.SG.
5. We are also investigating an un-related incident of a small trackside fire in the tunnel between Marina Bay and Raffles Place MRT stations that occurred yesterday afternoon.