SINGAPORE: The 26 defective SMRT trains which had hairline cracks were not sent back to its manufacturer for replacement works all at once as they were still fit and safe for service, the Land Transport Authority (LTA) said in a statement on Wednesday (Jul 6).
LTA explained that in July 2013, hairline cracks on the surface of the car-body bolster - which supports the car-body to rest on the bogie (framework carrying wheels) - of 26 trains were found during a routine inspection.
The location of the car-body bolster. (Graphic: LTA)
It added that 22 of the 26 trains were in service at the time. No cracks were found on other components of the trains, LTA said.
The authority added that the hairline cracks were due to "localised impurity in the aluminium car-body material that occurred during the manufacturing process".
"LTA engineers and its contractor assessed that the hairline cracks would not affect the operational safety of the trains. To confirm this, LTA further sought the opinion of an independent third-party assessor, TUV Rheinland, which concurred that the trains were safe to operate," it said.
AFFECTED TRAINS PROGRESSIVELY SENT TO MANUFACTURER SINCE JULY 2014
According to the statement, LTA said the most effective way of addressing the defect was to replace the entire car-body shell.
"As the trains were under warranty, we required the contractor to replace the entire car body shell," LTA said. It added that the affected trains have been progressively sent back to its factory for rectification works since July 2014, and that shipping costs are borne by the contractor.
It added that the replacement will take up to four months for each car body.
As of Wednesday, car-body replacement works for five of the 26 trains have been completed, while the car-body of the sixth train is being replaced.
LTA also explained that it sends only one train back to the factory in China at any one time to minimise the impact on train operations.
"We did not send all of the trains back at once as they were still fit and safe for service and we wanted to ensure sufficient train-availability for commuters," it said.
BATTERY AND DRAUGHTSCREEN ISSUES
LTA also revealed that it discovered issues with the trains' battery and draughtscreen before they were deployed for passenger service.
The trains, which were progressively put into service from February 2011, were first put through testing and commissioning. During a test, the cover of a train battery housing flew open due to a build-up of gases, LTA said.
"The manufacturer took immediate action to replace its supplier and improved the design of the battery housing for all affected trains," the statement said. "Incidents of cracks of the draughtscreen (glass panel found at the side of a row of seats) on five trains were also discovered. These were found to be caused by errors during the installation process and unrelated to the hairline cracks found on the 26 trains’ car-bodies."
LTA added it is "not unusual" to find defects on new trains, and that it takes action to have them rectified by the manufacturer.
TRAIN SERVICE AVAILABILITY WILL NOT BE AFFECTED: SMRT
Public transport operator SMRT said in a statement to the media that train service availability or frequency will not be affected due to the recall of the 26 trains, as they are being sent to the factory in "small batches".
SMRT's Vice President of Corporate Information and Communications Patrick Nathan added that the trains, which were discovered to have hairline cracks, are the newest in its fleet serving the North-South East-West Lines.
"Passenger safety is paramount to SMRT, and under no circumstance will this be compromised. Any train that is assessed to be defective or unfit for passenger service is not put into service," Mr Nathan said.
REPAIRED TRAINS FARING WELL: CSR SIFANG
Train manufacturer CSR Sifang said in a press release on Wednesday that some of the trains have been repaired and sent back to Singapore.
CSR Sifang also confirmed that the root issue was due to the trains' aluminium alloy, adding that this does not pose a safety risk.