Preliminary investigations indicated that faulty couplers - devices that joins one train to another automatically - failed to operate two weeks ago, causing a disruption on the North-East Line (NEL), which affected 50,000 commuters over a two-hour period.
SBS Transit, operator of the NEL, told The Straits Times that a train which was stalled by a short circuit had to be pushed by a rescue train - but couldn't do so because of faulty couplers. The incident is believed to be the first of its kind here which caused 250 passengers to be stranded in the train for roughly an hour on 19th of June.
For the coupling to work, one train has to approach another at low speeds to come into contact, after which the couplers of both trains will be connected automatically, according to SBS Transit spokesman Tammy Tan. "Electrical control signals and compressed air can also be connected between the two trains via the coupler," she added.
For unknown reasons, the coupling mechanism only worked after passengers were evacuated via the emergency ramps after a failed second attempt. "Why the coupling failed is the exact focus of our investigations," said Ms Tan.
The Land Transport Authority (LTA) is said to hold investigations as well, which will not only cover the mechanical issues of the breakdown but also incident management. It is believed the investigation will take up to three months to complete.
According to guidelines, passengers have to be evacuated from a stalled train within 30 minutes of a breakdown - a guideline not followed by SBS Transit in this particular incident. Transport Minister Lui Tuck Yew reacted strongly to the incident, and wrote in a Facebook post saying he was "dismayed at how the incident was managed".
