Rail operator SMRT yesterday explained the causes of three recent disruptions on its train lines, saying two were due to human error, and the third, equipment failure.
It had been asked by Transport Minister Lui Tuck Yew a week ago to furnish an update on its investigations into the delays on the North-South and East- West lines.
In the most recent incident, on Jan 22, the "oversight and non-compliance" of a train captain caused an hour-long disruption near Tanah Merah. The driver has been taken to task for not following a signal light on the track between the Expo and Tanah Merah stations, said SMRT spokesman Alina Boey.
Because of his action, train service had to be suspended while SMRT engineers checked that the network was working safely.
The Straits Times understands the driver failed to stop and wait for authorisation to drive on, when he got to the junction connecting the Changi extension to the East-West Line to Tanah Merah.
Trains that pass signal points without authorisation could potentially damage the tracks.
When that happened, SMRT locked down the track as part of its standard safety procedure and checked for damage to the area.
In the second incident, a technician failed to close two circuit breakers after a routine nightly service of a train. This caused the train's battery to drain to a level that automatically triggered a safety mechanism to prevent it from moving further.
The train stalled between Yio Chu Kang and Ang Mo Kio stations at 8.11am on Jan 20. SMRT used the train behind to push the stalled train to Ang Mo Kio, where passengers began alighting at 8.54am. Some 19,000 commuters were affected.
Ms Boey said the technician at fault has also been taken to task and pre-launch train checks will be supervised more thoroughly.
The third disruption, on Jan 11, occurred when a damaged cable caused a train to stall between Kranji and Yew Tee stations, so commuters had to get out and walk on the tracks to the station platform.
The cable, worn out by chafing against an installation bracket, cut off the power supply between the two stations.
Ms Boey said the cable has been repaired, and system-wide checks show there are no other points that might be worn out.
SMRT is also putting in place a condition monitoring system, she said.
Meanwhile, a track fault delayed train service on the North- South Line last night. SMRT is investigating why trains that passed a point on the tracks were switched to manual mode.
This restricts them to a speed of 18kmh, which led to longer journeys for commuters travelling between Ang Mo Kio and Marina Bay both ways.