Singapore's third oldest MRT line, the North-East Line (NEL), will undergo a major renewal project next year, to upgrade its trains, track components, and power and signalling systems.

As more engineering hours will be required to perform some of these works, the operating hours along stretches of the NEL will be shortened during certain periods, and commuters will have to use shuttle buses instead.

A similar early-closure late-opening programme was implemented for the North-South and East-West lines (NSEWL), the island's oldest lines, a year ago. Transport Minister Khaw Boon Wan, who announced the NEL upgrading on Monday (17 December), said the management of SMRT, the NSEWL's operator, underinvested and did the minimum when the lines needed upgrading and intensified maintenance.

"The cumulative effects of their decisions in those years were only corrected in recent years, at great inconvenience to commuters. We have learnt this hard lesson. We are determined not to have it repeated," Mr. Khaw said.

The NEL, which is operated by SBS Transit, was opened in 2003. The NSEWL opened in 1987. "When MRT lines are young, the current engineering hours of three to four hours per day, are enough. But as the lines age, we have to intensify maintenance," Mr. Khaw said.

The extended engineering hours for the NEL will give rail engineers much needed time to renew parts of the power and signalling systems and to replace rail crossings and tracks, he added. Mr Khaw said, "I know this will inconvenience commuters and I thank them for their support and hope to continue to have their kind understanding."

The Land Transport Authority (LTA) also signed a $117 million contract to upgrade the NEL's 25 first generation trains on Monday. With the overhaul, the trains' interior will get a facelift, and the air-conditioning, ventilation and passenger information systems will also be upgraded. Ageing electrical components and mechanical systems will also be replaced.

The LTA will also install condition monitoring systems on the trains to facilitate early warning of equipment deterioration

Mr. Khaw said the cost of the train upgrading will be fully paid for by the Government under the New Rail Financing Framework. The enhancements will benefit the 600,000 commuters who take the NEL each day. Mr. Khaw said rail reliability has improved and the authorities and operators have 'turned the corner', although it is still a work-in-progress.

"This is not to say that there will be no more train disruptions but train delays have become much less frequent and the situation continues to improve," Mr. Khaw said. In the past 11 months, trains on the North-South Line travelled an average of 824,000 train-km before encountering a delay of longer than five minutes, improving 10 times from 89,000 train-km in 2017. Mr. Khaw said this was a "highly commendable performance".

Meanwhile, the NEL has consistently exceeded the long-term mean kilometre between failure target of one million train-km this year, he noted.