SMRT Corp will reschedule its long-term track upgrade and renewal programmes to focus on finding the root cause of what crippled the entire North-South and East-West lines on Tuesday evening.
In a statement yesterday, the public transport operator said this was so that "priority for track access during the limited maintenance hours at night can be given to immediate remedial actions".
The operator will continue its tests and investigations through the weekend, including re-enacting, where possible, "the conditions under which the series of power trips was observed".
SMRT added that it was working with external experts to review the robustness of its power network, and to find ways to further segment it to avoid a similar network-wide power failure. It has brought in some retired former staff with experience in network power issues to help investigate.
The Land Transport Authority will also bring in an independent consultant specialising in transit power systems to examine the network as early as this month.
Tuesday's breakdown, which affected an estimated 250,000 commuters, was caused by a series of power trips along both lines.
So far, three possible causes have been identified - worn cable insulation, tunnel water leakage, and a glitch in a power substation.
SMRT said it had "advanced the procurement of additional condition monitoring systems" that were being developed. These systems are meant to detect changes that might indicate an imminent component failure. It also ruled out a defective train as the cause of the shutdown that hit 54 stations, saying that it was "highly unlikely".
Meanwhile, checks have been completed on all equipment that could have led to the disruptions.
SMRT chairman Koh Yong Guan again apologised for the disruption, and said that the company's board and management "take full responsibility" for it. "In particular, we apologise to our Muslim commuters who were returning home to break fast," he said, adding that full support had been given to staff to establish the root cause of the incident and to prevent a recurrence.
The company also acknowledged gaps in its service recovery, adding that bus bridging services - which ferry commuters between the affected stations - could not be activated on Tuesday because all available buses had already been deployed to boost daily services, which were made free.
MP Seng Han Thong, deputy chairman of the Government Parliamentary Committee for Transport, urged SMRT to be transparent with its recovery operations and efforts.
"I trust commuters will be able to understand at this difficult time. We have to work together so the system can become more reliable," he said.
