The MTR today encountered fresh problems when a line had to be closed due to technical glitches for the second time in 24 hours.
Services on the Eastern Line from Lo Wu to Hung Hom were halted for around seven minutes due to signalling problems, an MTR spokesman said, causing staff to close Fanling station for safety reasons.
Passengers complained that they were forced to wait for a train, for more than 10 minutes in some cases, after services were temporarily halted from around 7.40pm.
MTR infrastructure general manager Terry Wong Wing-kin apologised on a radio show for the incident. He said the company had been investigating the problems and that it was unclear whether they were related to a service halt yesterday.
The MTR East Rail Line came to a halt for 36 minutes yesterday morning after the train tracking system at the central control centre stopped working. Six trains were stopped between stations for up to 20 minutes during the disruption.
Station platforms grew crowded after all trains were stopped from 8.09am. They started running again at 8.45am but some services were still affected as late as 11am.
Lawmakers crticised the delay in notifying the media and public, with news of the disruption only released at around 8.30am.
Initial announcements in MTR stations said trains would be delayed by about five to 10 minutes, but passengers were later informed all services were being suspended on the line.
"Signal problems can usually be fixed within 10 minutes according to our past experience. But this time, when fixing it, we found that a longer time was needed," said MTR east region's head of operations Francis Li Shing-kee. He apologised to passengers who had been affected.
The rail company said the defect was in a router in the data network that receives signals from trains. The signals were lost, so the control centre could not track the trains and services were stopped as a safety measure.
The router had never failed in the 11 years the network system had been in use and there would be an investigation into what went wrong, said MTR infrastructure general manager Terry Wong Wing-kin.
The router breakdown also meant the back-up data system failed to switch on automatically and had to be turned on manually, Wong added.
Some passengers did not hear any announcements for 20 minutes. "I kept waiting, until they told us to leave because the trains couldn't run. I went to find a bus, then we heard on the bus that the trains were running again, so I came back," one woman said.
At 11am, one train stopped at Sha Tin for at least 10 minutes. The platform sign changed to "not in service" after passengers boarded. Li explained the signals were unstable on two occasions after service resumed.
Tang Ka-piu, Federation of Trade Unions lawmaker, said the MTR had been irresponsible in taking 20 minutes to notify the public, adding that frequent disruptions were raising concerns about its quality of service.
The Transport Department said the MTR had notified it of the service disruption within the required eight minutes.