Mass Transit Railway (MTR) train services in Hong Kong were disrupted for six hours during peak hour on Tuesday morning (Oct. 16) due to a signalling fault, throwing the morning commute for millions into chaos, reported South China Morning Post (SCMP).

Four lines were affected

The disruption was said to be "unprecedented" as three lines broke down at the same time.

They were the Island, Tsuen Wan and Kwon Tong lines.

The signalling fault was first reported at around 5.30am.

But at 10.18 am, a fourth line -- the Tseung Kwan O line -- was also affected.

Unhappy about your #commute to work? #HongKong just saw an unprecedented 3-line signal outage on the most populated transport system, the MTR. Take a look at the madness that is not abnormal to folks who #work in HKG.🇭🇰 pic.twitter.com/8c76S8Fxic

— Rita Pang (@ritapang) October 16, 2018

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Commuters were told to take other forms of public transport instead.

The MTR has broken down and the queues for the bus are insane. pic.twitter.com/LpMqr7AncP

— Anth (@AnthHoKo) October 16, 2018

For those who were already inside the stations at the lobbies, they proceeded to the platform in 10-minute intervals.

But for some who could not wait any longer, they chose to jump over the railings and leave the stations instead.

Severe delay across 3 major MTR lines, staff is stopping passengers from entering the station pic.twitter.com/KUrjBMovSk

— Cosmo Lo (@locosmo) October 16, 2018

Train services started to resume at around 11.45am.

After the breakdown, operating staff had to drive the trains manually.

As a result of the manual operation, trains ran at a slower speed -- 23km/h instead of the usual 60km/h.

MTR warned of possible delays in 2016

In 2016, the MTR Corporation had warned that the first trains of the day might be delayed, according to another report by SCMP.

This is due to a series of tests that had to be done over the next 10 years in order to upgrade the signalling systems of seven railway lines.

The upgrades are supposed to raise the train network's capacity by 10 per cent from 2018 to 2026.

MTR Corp operations director Adi Lau said on Tuesday that they are looking into the cause of the disruption to see if the signal failure was due to a power supply issue at its control centre.

Best in the world

Hong Kong's MTR has been acknowledged as the best in the world.

Well-known vlogger NAS Daily even did a video on the MTR, calling it the "World's Best Metro".

He also cited the HK$1 million (S$175,400) fine MTR has to pay if a train is late for more than 30 minutes as the reason why trains are on time for 99.9 per cent of the time in the city.