Joo Koon train collision a serious matter; could be due to bug in signalling system, say experts

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28 people were injured in an MRT collision at 8.20am at Joo Koon station. This led to major delays on the East-West Line. The Straits Times looks at the how day's events unfolded.
SIT's Assistant Professor Andrew Ng believes the incident was caused by a "bug" in the signalling system. ST PHOTO: JONATHAN CHOO

SINGAPORE - Observers and transport experts said that Wednesday morning's (Nov 15) collision between two MRT trains is a "serious" matter, and urged the authorities to get to the root of the problem as soon as possible.

While reasons for the accident at Joo Koon MRT station are scant, Assistant Professor Andrew Ng from the Singapore Institute of Technology's engineering cluster said a "bug" in the signalling system software could be the culprit.

The signalling system ensures that trains maintain a safe distance between each other by tracking their locations on the network.

According to train operator SMRT and the Land Transport Authority (LTA), a train heading westwards stalled at Joo Koon station at 8.18am. About a minute later, a second train stopped behind the first train, but soon after, moved forward unexpectedly and "came into contact with the first train".

Prof Ng said that an "incorrect signal" or command could possibly have been sent to the second train, instructing it to move.

"There could be some fault in the processes in the signalling system, that they are not able to detect the presence of the first train," Prof Ng said. By the time it did so, he said, the collision was inevitable.

"Trains can't stop immediately, even though the brakes are applied, (it's) like a car. It will take a distance to come to a full stop," Prof Ng added.

Prof Ng said this was a "serious" case, but also noted that the second train did manage to stop behind the first one, before moving forward again. However, Prof Ng questioned if a safe distance was maintained between the two trains when that happened.

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Mr Ang Hin Kee, the deputy chairman of the Government Parliamentary Committee for Transport, said he was concerned by the incident, which resulted in 28 people being injured.

Mr Ang said he wished those injured a speedy recovery and said it was "important to quickly identify the cause of the collision and to provide assurance to all commuters that the matter is being addressed".

Associate Professor Lawrence Loh, from the National University of Singapore's Business School, said: "The SMRT incident this morning presents a whole new dimension to the problem. While the recent disruptions merely give rise to inconveniences for commuters, we now see human injuries."

SPH Brightcove Video
Two MRT trains collided at Joo Koon station on Wednesday morning, injuring 29 people. Here are five things about the accident.

Prof Loh, who is deputy head of the school's strategy and policy department, added: "We can't have more of the same. We need a bold relook of the solution (to the MRT problems)."

The Workers' Party, in a statement, called on SMRT to render all necessary support to those injured, and cover all their medical expenses, including any long-term treatment costs.

"The collision suggests a failure of the systems that ought to prevent such an event, which presumably should have several levels of checks," it said. "While facts are still emerging, we ask that the LTA will work with the SMRT to undertake an exhaustive root cause analysis and make the necessary system improvements to minimise the risk of such an accident recurring."

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