SINGAPORE - The Japanese-Chinese consortium which supplied the 26 trains with hairline cracks won subsequent tenders fairly, said Transport Minister Khaw Boon Wan in Parliament on Tuesday (Aug 16).
The actions of the consortium, Kawasaki-Sifang, in rectifying the defects at their own expense was also exemplary, and the issue was resolved when other tenders for trains were called, he added.
"Our train tenders have always been conducted in an open and transparent manner, and are based objectively on quality and price assessments. Kawasaki-Sifang won the subsequent tenders fairly," Mr Khaw told the House.
He was responding to questions from MPs, regarding the train defects which were first brought to light by Hong Kong media FactWire last month.
In 2009, Kawasaki-Sifang was awarded an initial $368 million contract to supply 22 new trains for the North-South and East-West lines, with more trains purchased later.
The consortium continued to win more orders, including a $749 million contract in 2014 to supply 91 four-car trains for the upcoming Thomson-East Coast Line.
Mr Khaw said that following the discovery of the cracks in 2013, Kawasaki-Sifang had agreed to replace the bolster parts, previously made in China, with new ones cast in Japan. The consortium also agreed to bear all the rectification costs, including shipping the trains back to China for the work.
To date, five of the 26 trains have been rectified, and another one is currently in Qingdao, China, undergoing rectification.
The entire train car body, on which the bolsters are welded to, would also be replaced in the process. The bolster is an aluminium alloy structure found under the train carriage.
Mr Khaw said: "The concern about the defects had thus been resolved when we called the tender for more trains in 2014 and 2015".
Investigations showed that defects in the manufacturing process resulted in impurities being introduced in the aluminium material, resulting in cracks developing over time.
He said the public was not told of the hairline cracks on the China-assembled trains because they did not pose a safety risk, and the manufacturer took full responsibility for them.
Also, the rectification schedule - which required trains to be sent back progressively to China - did not affect train services and capacity levels, Mr Khaw added.
He told the House: "Had any of these factors not been satisfactorily dealt with, LTA (Land Transport Authority) would have publicised the defects... Meanwhile, we continue to monitor the affected trains closely, including those which had been rectified by the manufacturer."
He also added: "The hairline cracks do not compromise the safety of commuters. The trains are designed with a large safety margin... The bolsters are able to take more than three times the maximum stress that they may experience during operations. The cracks have not reduced this safety margin."
Separately, the LTA also appointed an independent assessor, TUV Rheinland, which affirmed that the trains were safe to operate despite the cracks, he added.