A blaze that started in the electrical room at Senja station damaged circuit breakers and shut down service along the Bukit Panjang LRT (BPLRT) line yesterday evening.
The major disruption left thousands of commuters stranded during the rush hour.
The fire started at about 5.45pm. Around 7pm, transport operator SMRT said service would not resume that evening. It is investigating the cause of the fire.
"SMRT is working to recover BPLRT services (for Tuesday) morning," said SMRT Trains managing director Lee Ling Wee.
The fire alarm at Senja station was activated at about 5.45pm, and smoke was reportedly seen at the station's plant room, said Mr Lee.
The Singapore Civil Defence Force extinguished the fire within 10 minutes with a single fire extinguisher, but not before the power tie-breakers were damaged.
A power tie-breaker is an electrical circuit breaker that connects two sectors of the power rail, which supplies power to the train.
Yesterday's disruption coincided with the rush-hour crush, and left commuters standing shoulder-to-shoulder at LRT station platforms.
SMRT activated 30 free shuttle buses to ferry travellers between all 14 affected stations.
The fire was the second of two incidents that hit the BPLRT line in the evening.
Earlier, at 5.30pm, a power trip between Pending and Jelapang stations caused service to be disrupted along the entire line, and commuters on one stalled train had to walk along the tracks.
A video posted on Facebook showed more than 40 commuters walking on the tracks towards Pending station.
With the LRT service down, commuters had to rely on free bus services or shuttle buses to get home for several hours.
At Choa Chua Kang station, an interchange between the LRT line and North-South MRT Line, about five SMRT employees were seen ushering commuters to buses, and helping with crowd control.
But while many observed that buses arrived promptly to ease the crowds at the stations, for some it was still a long wait.
One worried father, a PUB technician who wanted to be known only as Mr Jana, waited for more than an hour at Senja station for his two daughters who were stuck in Choa Chu Kang.
"That's how the LRT is," said the 55-year-old. "(They can't) say it's maintenance problems, breaking down is pretty common for the LRT system."
Yesterday's shutdown is the third incident to hit the Bukit Panjang LRT line in two weeks. The previous two disruptions occurred on Sunday and Feb 24.
Last week, SMRT held a press briefing to address concerns after a spate of breakdowns on its rail lines, and said it would bring forward plans for a maintenance operations centre.
Warehouse assistant Richard Ang said the breakdowns affect the confidence that commuters have in the system. "There's no feeling of security, or knowing the LRT will be around when you need it."
Other commuters were worried train services would not be restored by morning.
"What if I'm stranded at Senja LRT (station) and I'm late for work? It might be safer to just take a cab," said shop assistant Wendy Lay, 35.
Mr Liang Eng Hwa, the MP for Zhenghua constituency, urged both SMRT and the Government to find the root cause of the fire.
"It's actually quite a big disappointment that this has happened so many times," he said. "LTA and SMRT need to get their act together to really bring up the reliability of the system and win back the public's confidence."
Mr Lim Biow Chuan, who sits on the Government Parliamentary Committee for Transport, said SMRT should provide compensation to commuters. "It might cost them a lot, but I think they should show some contrition."