Thousands of travellers faced lengthy delays yesterday as an electrical fault on the East Rail Line forced a partial closure of the route - the fourth major incident on the MTR network in two months.
Almost four hours of chaos began shortly before noon when a Hung Hom-bound train broke down near University station in Sha Tin. Eyewitnesses reported seeing a flash outside the train, while some of the lights in the train's carriages went out.
Video footage taken by a passenger shows a 10-second burst of light on a pantograph - the apparatus that connects the train to the overhead power line. The train came to a halt near the platform of the station, which serves Chinese University.
The MTR Corporation blamed a faulty insulator between University and Fo Tan stations for the problems.
With the southbound track closed, all trains were diverted onto the northbound track, and service frequency was reduced to every 20 minutes. Trains on the East Rail Line usually run up to every four minutes on a Sunday.
A free shuttle bus was also introduced to connect Tai Po Market, University, Fo Tan and Sha Tin stations.
MTR staff carried out urgent maintenance work on the line, with firefighters on standby. But passengers complained that, in some cases, their travel time had more than doubled.
The line reopened at 3.20pm, but shortly afterwards it was reported that passengers on a packed train at Kowloon Tong were told to disembark.
The Transport Department has ordered the MTR Corporation to submit a report on the disruption.
Yesterday's shutdown was the latest in a series of technical problems that have put a dent in the mass-transit system's reputation for reliability.
Last month, a light-rail train broke down in Yuen Long after a pantograph was damaged. Five routes were redirected and eight stations were closed for almost three hours.
In December, the roof of a light-rail train caught fire. That came just 24 hours after a power failure halted services on the Tseung Kwan O line for almost five hours, forcing 150 passengers to walk along the track to Yau Tong station and causing transport chaos.
Staff unions and lawmakers have questioned whether subcontracting of maintenance work has led to problems.
Sunday is typically a busy day on the East Rail Line, which serves the racecourse at Sha Tin. However, last week's Sha Tin race meeting took place on Saturday.
Watch: Hong Kong's MTR during peak hours