SINGAPORE - The Bukit Panjang LRT line, which was shut down on Monday evening due to a fire, will not resume on Tuesday morning on both bounds.

In a Facebook post early on Tuesday morning, SMRT said its engineers had worked through the night and will continue to recover LRT services as soon as possible.

"Preliminary investigations indicate that a tie-breaker overheated and caught fire. We are still investigating the root cause of the incident," the train operator wrote.

It said public bus services provided by SMRT and SBS Transit in the Bukit Panjang area will be free. There will also be some 40 free bus bridging services for both Service A and Service B from 5am, SMRT said.

Additional SMRT staff will also be deployed at bus bridging points at Bukit Panjang LRT stations to assist commuters.

The Land Transport Authority in a Facebook post early on Tuesday said it will continue to work with SMRT to restore train service as soon as possible.

At around 8am, SMRT tweeted that testing of the trains have started.

Ms Jessica Tan, 44, who teaches part-time at a childcare centre, took leave on Tuesday because she was concerned about her daughter getting to school on time. Her daughter is in Secondary 2 at Zhenghua.

"Normally she wakes up at 5.45am but today she had to wake up at 5.15am. I wanted to take a taxi but when we came out we saw all her classmates across the road already waiting for cabs," Ms Tan said.

"It's good they gave us advanced warning, but the signs were very small when we were coming out of the interchange. It should be more obvious whether you should take Bus A or B."

Mr Subramaniam, 60, a security guard, said: "The timing is okay but the bus was quite crowded. I think they need more buses."

Ms Janice Ng, 40, a purchaser, woke up 40 minutes earlier because she did not know how long the buses would take. "It's been quite smooth though."

When asked if she was annoyed, she shrugged and said: "We have no choice."

Transport Minister Lui Tuck Yew briefly visited the bus stop outside Choa Chu Kang MRT around 8.30am with Land Transport Authority chief executive Chew Men Leong to observe the running of the shuttle buses. Mr Lui also spoke with SMRT staff on the ground.

The breakdown affected thousands of commuters during Monday's evening peak hour commute. It is the latest in a spate of disruptions to hit the rail network in the past few weeks.