Singapore's plans to expand its rail network by more than 50 per cent by 2030 will be delayed as a result of the impact of Covid-19.

But the Government still aims to hit this target by the early 2030s, Transport Minister Khaw Boon Wan said yesterday.

"There will be some delays because of Covid-induced impact on the availability of construction workers," he said. "But the intent to significantly expand our MRT network remains unchanged."

Singapore's current rail network spans about 230km.

The Land Transport Authority (LTA) had said that it wanted to expand the rail network to about 360km by 2030, which would connect eight in 10 households to a train station within a 10-minute walk.

Rail lines that were due to be completed in the next decade include the remaining phases of the Thomson-East Coast Line (TEL), Jurong Region Line and the first part of the Cross Island Line.

Stage two of the TEL was set to be completed later this year. It will link Woodlands South station to Caldecott station via Mayflower station. The Circle Line, Downtown Line and North East Line were also due to get additional stations in the next decade.

LTA is currently assessing the impact of Covid-19 on its projects.

Mr Khaw said yesterday that measures to combat Covid-19 have resulted in a drop in usage of public transport, but demand will return with time.

Public transport ridership is now at about 40 per cent of pre-Covid-19 levels, after movement restrictions were eased last Friday.

Mr Khaw was speaking during an event at the Bishan Depot to start the decommissioning of Singapore's very first MRT trains.

The trains, made by Japanese manufacturer Kawasaki, have been used on the North-South Line and East-West Line (EWL) for more than 30 years. The 66 first-generation trains will be progressively replaced by new trains from Bombardier from next year.

Mr Khaw said that, other than expanding the rail network, ensuring rail reliability is another important task.

"This ethos is now deeply embedded in the corporate culture of our operators," he said, adding that rail operators SMRT and SBS Transit are now among the most reliable in the world.

The entire MRT network consistently exceeds a mean kilometre between failures (MKBF) of one million train-km, noted Mr Khaw.

MKBF, a benchmark measurement of rail reliability, refers to the mean distance between a train fault of more than five minutes. Between April last year and March this year, the MRT network achieved 1.4 million train-km between failures.

Mr Khaw said continued investment in maintenance and in assets renewal will be needed to maintain the reliability.

He added that based on data from last year, the EWL was the most reliable line and the most improved line in terms of rail reliability.

"The East-West Line has come a very long way, especially from the 2017 train collision incident, for which all of us would never forget."

He was referring to the incident in which a glitch in the signalling system of the EWL caused a collision between two MRT trains at Joo Koon station. Twenty-nine people were injured in the incident.

"The turnaround of EWL is a good story, that no matter how low we have fallen, with determination, we can rise again, to emerge stronger," Mr Khaw added.