Assessment of Safety Risks of Defects Found on 26 MRT Trains
Ministry of TransportSpeakers
Summary
This question concerns the safety risks and repair procedures for 26 defective MRT trains as raised by Assoc Prof Daniel Goh Pei Siong. Minister for Transport Mr Khaw Boon Wan stated that hairline cracks on bolsters did not compromise safety as the trains maintained a safety margin of three. He noted that independent assessor TUV Rheinland confirmed the trains are safe to operate while the Land Transport Authority continues close monitoring. The Minister explained that entire car-bodies require replacement because bolsters are welded to them and the defect was isolated to a specific batch of aluminum. Finally, he shared that the manufacturer opted to use Japanese-made bolsters for replacements and confirmed that other train components remained unaffected.
Transcript
12 Assoc Prof Daniel Goh Pei Siong asked the Minister for Transport with regard to the 26 defective MRT trains (a) whether the defects being not "safety-critical" meant that they pose zero safety risks for commuters; (b) why is it most effective for the car-bodies to be entirely replaced when cracks have been found only on the bolsters; (c) what are the risks for cracks to happen on other components of the car-body; and (d) whether the monthly safety assessment is focused only on the found defects or conducted for the entire train.
The Minister for Transport (Mr Khaw Boon Wan): The hairline cracks do not compromise the safety of commuters. The trains are safe. The trains are designed with a large safety margin of three. What it means is that 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. In other words, all these can be tested in the laboratory and you can check it out that, despite having the cracks, the safety margin of at least three is still being preserved. The cracks have not reduced the safety margin.
But to be absolutely sure, the Land Transport Authority (LTA) had appointed an independent assessor, TUV Rheinland and the assessors confirmed that the trains are entirely safe to operate. In any case, as I said just now, LTA, SMRT and Kawasaki-Sifang continue to monitor closely the affected trains, including those that have been repaired and returned to service.
Kawasaki-Sifang decided that the most effective repair method was to replace the entire car-body. This is because the bolster, where the hairline cracks are found, is welded to the car-body. As Kawasaki-Sifang does not have the necessary facilities in Singapore to refit the trains with new car-bodies, the trains have to be shipped back to Kawasaki-Sifang's manufacturing base in China.
The cause of the cracks was traced to a specific batch of aluminium material used for the manufacturing of the train bolsters only. Other parts of the trains are not affected.
Mdm Speaker: Assoc Prof Daniel Goh.
Assoc Prof Daniel Goh Pei Siong (Non-Constituency Member): I thank the Minister. What is the difference between the bolsters being made in Japan versus those being made in China? Why is the decision now for the bolsters to be made in Japan rather than in China? Is there a confidence issue with manufacturing of train parts in China and, if it is so, is Ministry going to take this into account for future contracts?
Mr Khaw Boon Wan: What is the difference? One is made in Japan and one is made in China. Is there a qualitative difference? I do not know. But the decision − using new bolsters from Japan − is made by the manufacturers themselves. They said, "Well, since it is defective, I will replace your bolsters". And they offered to now use a Japanese bolster and, of course, we said "You are welcome to use Japanese bolsters". In fact, the first generation of Kawasaki trains all used Japanese bolsters. I do not think we need to read anything more into this. I do not want to create a diplomatic problem.