Services on the Punggol LRT line were disrupted by a signalling fault for about 45 minutes yesterday.

The disruption was first announced by rail operator SBS Transit in a tweet at 12.02pm. It tweeted at 12.14pm that train services had resumed.

And at 12.25pm, SBS Transit said bridging buses and free bus rides at designated stops had ceased.

It apologised to all passengers for the inconvenience caused.

Senior vice-president of SBS Transit corporate communications Tammy Tan said five light rail vehicles (LRVs) had stalled on the tracks due to the fault.

Passengers could not be evacuated to the station via the tracks because of lightning warnings, said Ms Tan.

She added that air-conditioning and lighting continued to be available on board the LRVs and that SBS Transit staff had remained in contact with the passengers.

The cause of the fault is being investigated.

Ms Diantha Chong, 24, a market research associate, was on her way to a fitness class when her train stopped.

"My ride to Punggol MRT station is usually only 10 minutes. They said the delay would only be 15 minutes, but I was stuck on the LRT train for almost an hour and missed my fitness class," she said.

"There were no clear instructions given during the disruption - it made me pretty upset as my fitness studio charges fees for missing classes," she added.