The carriage in question was removed from the track, it said.

Bosses at the embattled operator had apologised for the disruption, which caused the closure of University station and travel woes for tens of thousands of commuters.

The corporation’s head of operations engineering, Tony Lee Kar-yun, said the MTR Corp would investigate the circumstances surrounding the incident.

Earlier, Lee said they were up against the clock in resuming services before the evening rush hour begins.

“We are racing against time to restore services before the next peak hours,” he said at 1pm.

“We encountered challenges with putting the carriage back on the track.”

This was the first time it had encountered such an incident, the operator said.

Lee said the first carriage of the bogie derailed 500 metres north of University station during routine track maintenance on the East Rail line, which runs between Hung Hom in Kowloon and Lok Ma Chau or Lo Wu at the border.

“The carriage in question is very heavy, at 80 tonnes, and it went off track at a curve location, so we have to put it back literally inch by inch” he said.

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“There are about 100 workers helping to restore it, and we have firefighters’ help as well.”

Sammy Wong Kwan-wai, MTR Corp’s chief of operations, apologised to commuters for the delays and admitted the rail firm could have done better in helping passengers access replacement services.

“It will take longer to take the shuttle buses partly because of their smaller capacity compared to a train that normally carries nearly 3,000 people, and there were a couple of road accidents on Tolo Highway, which worsened the situation,” he said earlier.

Michael Tien Puk-sun, a lawmaker and former chairman of the Kowloon-Canton Railway Corporation, estimated the MTR Corp would be fined up to HK$20 million (US$2.56 million) by the government, based on the duration of the service suspension.

“This once again shows the downside of overrelying on railway services,” he said. “In the long run, the government should consider striking a balance by providing a higher proportion of alternatives, such as public buses.”

According to the MTR Corp’s annual report, the company’s market share grew to 49.3 per cent of public transport last year from 49.1 per cent in 2017, with the rest taken up by public buses, minibuses, trams and ferries.

“The management needs to find out the root problem of the incident, which is very rare,” he said. “We frontline staff face lots of pressure when services break down. I hope this is the first time and the last as well.”

The MTR Corp offered free shuttle buses between Sha Tin and Tai Po, but it urged commuters to take other modes of transport.

It mobilised 200 shuttle buses, mainly serving Tai Po, University, Sha Tin and Fo Tan stations, and deployed an extra 150 staff members to maintain order.

As of noon, about 1,000 commuters were queuing for buses inside the Tai Po Market station concourse, weaving from the entrance to the underground tunnel near Uptown Plaza. Crowds were also waiting at Sha Tin station for the shuttle service.

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A 67-year-old security guard, who only gave his surname Tong, arrived at the station at about 8am to catch a train for Sheung Shui, but was still in the queue as of 11.35am. Normally the train journey takes him 10 minutes.

“I’m supposed to get on the train by around 8am, but until now I can’t even get a ride,” he said. “I’m already very late, but there really isn’t much choice. I really hope this issue can be resolved soon.”

Suki Yip, 23, a student at Chinese University, was at Sha Tin station on her way to campus at University station when she found out services were suspended.

“I’m very worried because I am trying to take the shuttle buses instead, but it seems like there are so many people,” she said.

“It’s quite troublesome for me and I hope this will be over soon.”

Hundreds were also queuing at Sha Tin station for shuttle buses, with the lines so long they snaked into the New Town Plaza shopping centre next to the station.

Demand for taxis and other private hire services had rocketed in the area. A Post reporter waited an hour for a taxi at Sha Tin station.

Ride-hailing app Uber was so popular its fares had surged three times the usual rate.

A trip from Sha Tin to Tai Po Market station typically costs between HK$80 to HK$100 through the service, but shot up to HK$310 (US$40) at 9.40am.

Some commuters waiting for shuttle buses at Tai Po Market station complained they had been queuing for an hour and still could not get on one.

The knock-on effect left surrounding roads clogged, with Tolo Highway, which connects Kowloon to the northern New Territories, especially busy.

At around 10am, past the normal rush hour, public buses heading to urban areas in Kowloon and Hong Kong Island were still packed with passengers.

At Tate’s Cairn Tunnel Toll Plaza, an interchange station connecting New Territories East passengers to the city centre, buses were fuller than usual and skipped the stop.

Passenger Alex Ko was still on the way to his office in Causeway Bay at 10.30am despite leaving his home in Sheung Shui three hours earlier.

He had only managed to get to University station on an MTR shuttle bus, not even half the distance to Causeway Bay.

“There was no order in the queue and many people cut in line,” Ko said of the situation in Tai Po Market station, where he boarded the bus.

The East Rail line connects mainland China with the bustling urban areas of Kowloon. It also serves residents in New Territories wanting to access the city centre.

The Electrical and Mechanical Services Department, which received the MTR Corp’s notification of the incident at about 4am, said it required the corporation to investigate the incident and submit a report on the causes and measures that would be taken to prevent it from happening again.

Meanwhile, at 8.45am, rail services were hit by fresh delays on the Tsuen Wan line connecting Central and Tsuen Wan of five to 10 minutes after anti-government protesters blocked train doors in the latest instalment of the non-cooperative campaign against the MTR Corp.

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It marked the third time this week protesters tried to disrupt services, following similar incidents on Monday and Wednesday mornings.

The rail section affected by the protest resumed normal services from about 9.10am.

Additional reporting by Sum Lok-kei and Elizabeth Cheung