SINGAPORE - Faulty water discharge pumps were found at two other locations on SMRT's rail network, after such flawed pumps in Bishan caused flooding in an MRT tunnel.

These were uncovered by checks SMRT did after the flooding, Transport Minister Khaw Boon Wan said in Parliament on Tuesday (Nov 7).

They were at the tunnel portal near the Kembangan and Lavender stations.

At Kembangan, two out of eight pumps were not functioning properly while at Lavender, it was three out of four pumps, Mr Khaw added in his ministerial statement on the Oct 7 incident in Bishan.

But the remaining pumps at two other tunnel portal locations near Redhill and Changi were in serviceable condition.

These pumps discharge rainwater collected at stormwater sump pits into drains.

A failure by SMRT staff to maintain them at Bishan caused flooding in an MRT tunnel, forcing the shutdown of train services on Oct 7 for about 20 hours along a stretch of the North-South Line. Train services resumed only the next day.

Mr Khaw said SMRT is currently investigating the relevant teams from the Building and Facilities maintenance group that are responsible for the pumps at Kembangan and Lavender.

As for the maintenance lapse at Bishan, SMRT said on Monday (Nov 6) that disciplinary action will be taken against six employees who had falsified maintenance records between December 2016 and June this year.

Shedding more light on the group comprising a manager, an engineering supervisor and four crew members, Mr Khaw said three have been with SMRT for more than 20 years, including one who has been with the company for more than 28 years.

Of the remaining three, one has been with SMRT for little over a year, and the other two, for six and eight years, he added.

Reiterating what he said at a press conference in October, Mr Khaw said the tunnel flooding incident was "preventable".

"Why these float switches failed to function normally on Oct 7 is a subject of the ongoing LTA investigation," the minister added.