Probe must determine if the EWL disruption was preventable

Full accounting of incident will also go some way towards restoring public confidence

- Esther Loi

Train services along a four-station stretch of the East-West Line between Jurong East and Buona Vista will remain disrupted over the weekend, in a breakdown that has affected the commutes of more than 1.7 million passengers so far.

The disruption was caused by a faulty train that was returning to Ulu Pandan Depot on Sept 25. A defective axle box - a component on a train's undercarriage - fell out near Dover station. This caused the undercarriage, or bogie, to go off the rails.

It left in its wake extensive damage to the tracks and trackside equipment.

How did the axle box become dislodged from the bogie, and was the incident preventable, given the widespread use of preventive technology in rail maintenance? These are among the questions that the probe into the serious incident must answer.

Preventive maintenance has been a focus for SMRT. About nine years ago, for instance, the rail operator adopted a monitoring system that deploys sensors to scan the entire train fleet on the North-South and East-West lines for train wheel and axle defects. Axles connect the wheels of a train.

While it is unclear if such a system could have detected a defective axle box, the fact is that SMRT has been using technology to shore up its rail maintenance and better predict when parts will fail and need to be replaced.