SINGAPORE - On Oct 7 last year, train service along a stretch of the North-South Line was disrupted for 20 hours.

A storm water pit at Bishan had overflowed, flooding the MRT tunnel there and rendering train service on the affected stretch inoperable, affecting some 250,000 commuters.

Investigations later found that a team of six responsible for maintaining flood-prevention devices, from the Building and Facilities maintenance group, had falsified maintenance records.

In this video, Senior Transport Correspondent Christopher Tan talks about how he covered the incident, including obtaining the shocking picture of a train stuck in waist-high water in the tunnel.