SINGAPORE - SMRT will be replacing the power-supplying third rail at some locations with immediate effect, after hairline cracks were found on the joints.
The move comes after a team of experts warned on Tuesday that parts of the rail could have hairline cracks and asked for immediate checks to be carried out.
According to The Straits Times, the cracks are not of pressing concern, but LTA has asked SMRT to carry out the precautionary measure for added safety.
The recommendation by six experts is one of 33 suggestions made by the team to the Committee of Inquiry on what should be done to prevent breakdowns like the ones which occurred in Dec.
The suggestions covered six categories, including how to maintain wheel condition of trains and third rails to better monitoring of procedures and maintenance of assets.
Team leader David Ewins, professor of vibration engineering at Imperial College London's Department of Mechanical Engineering, said one crack was discovered on the northbound line between City Hall and Dhoby Ghaut stations. This was the site of the breakdown on Dec 15 last year.
Another crack was found on the southbound line between Orchard and Newton stations, where the second breakdown on Dec 17 occurred.
Prof Ewins also said both breakdowns were caused by 'a combination of events that were linked to each other', but it may not be possible to establish 'the exact sequence of events', reported The Straits Times.
The team of vibration, noise and rail dynamics experts agreed that the Dec 15 incident was likely to have been triggered by a damaged fastener in the third rail support assembly. This could have caused the claw holding the third rail to dislodge and sag marginally.
As for the Dec 17 incident, the panel presented two scenarios. One was that a train with damaged current collector devices was not spotted and rectified after the Dec 15 incident.
Another has to do with the cracked third rail which made the line more prone to vibrations.
The inquiry has heard evidence from a total of 100 witnesses so far since it started on April 16.