The Government will commission a formal Committee of Inquiry to look into the troubling spate of SMRT breakdowns, said Prime Minister Lee Hsien Loong yesterday.

The move comes as SMRT's North-South Line broke down again for seven hours yesterday morning, affecting 94,000 commuters heading into town on the last weekend before Christmas.

This was the second major disruption on the North-South Line in less than 36 hours, prompting the Land Transport Authority (LTA) to order an unprecedented shutdown of two SMRT lines for a thorough visual check of all trains and tracks.

As a result, the North-South and East-West lines will be open to commuters at 10 this morning, much later than their usual 5.30am start time. About 250 buses will provide free parallel services between the stations on both lines until the trains start rolling.

Yesterday's disruption started at 6.50am, eventually knocking out train travel in both directions between Marina Bay and Ang Mo Kio.

Northbound services resumed at about 9am, but southbound services were only gradually restored throughout the morning, regaining normal state at 1.48pm.

LTA and SMRT said that yesterday's breakdown had the same root cause as Thursday's - a misalignment between the track and the 'collector shoes' on the trains that draw power from it.

This time, it was two faulty sections of the track near Orchard station that caused as many as seven trains to stall.

Several trains had to be towed out of the tunnels and about 500 passengers had to disembark from their stalled train and walk 150m through the tunnel to Somerset station.

'Had it just been a one-off matter and then the matter is solved, then I think the operating agencies can take care of it,' said PM Lee, who is officially on leave but returned to LTA's headquarters yesterday afternoon to be briefed on the situation.

'But when the incidents happened again this morning, and the same thing, that meant that it wasn't a random thing. There's something more basic which has caused it and which we haven't quite pinned down yet.'

This is why the Government will appoint a Committee of Inquiry, which will study and publicly present evidence as to why the disruptions happened and how to make the system more robust and reliable, he said. It will be appointed within 'a couple of weeks'.

A Committee of Inquiry is a high-level probe typically chaired by a judge. In recent times, such committees were set up to look into the Nicoll Highway collapse and the escape of the terrorist Mas Selamat Kastari.

'We are taking it very seriously. I think public safety is an absolute,' said Mr Lee. But he also noted that the recent breakdowns were not primarily a safety issue.

'We are not talking about trains derailing or colliding with one another,' he said. 'It's an issue of operation, of providing the service without interruption or mishap. And I think given a bit of time, we will be able to solve it.'

Mr Lee also touched on criticisms that SMRT failed to give timely information to commuters about the breakdown, saying that it is something that LTA and SMRT will have to discuss and improve.

'The immediate concern will be with the people who are affected, the passengers who are in the trains who are trapped,' he said.

'And you have to let them know: Please wait or please walk, which do you want them to do?'

Minister for Transport Lui Tuck Yew paid a personal visit to the Toa Payoh, Newton and City Hall stations yesterday to see for himself whether SMRT had improved communications and crowd control procedures since Thursday night's breakdown.

'Overall, my personal impression today compared to what I read on Thursday when I was in Cambodia was that there is some improvement,' he said at a press conference in the afternoon.

The train operator stepped up the frequency of its announcements yesterday and recalled more staff - clad in easily identifiable yellow vests - to assist commuters at affected stations.

'SMRT has obviously taken on board some of the lessons that it learnt from the initial incident,' said Mr Lui. 'It has given better and more timely information, although I would say there is still some way to go.'

- end of ST article. Reprinted with permission.