The condition of the surge arrester could have deteriorated over time, LTA says in a review of the MRT outage on June 3

A faulty surge arrester was one of the causes of an MRT outage earlier this month, the Land Transport Authority (LTA) said.

On June 3, the service on the North-South Line (NSL) was disrupted for more than two hours during the evening rush hour after a lightning strike.

The condition of the surge arrester, which was intended to protect against lightning strikes, could have “deteriorated over time”, LTA added.

Lightning damaged the Kranji MRT power control box, causing a power outage

LTA released the results of an investigation into the June 3 MRT disruption in a Facebook post on Saturday evening (June 15).

It was said that a lightning strike damaged a trackside power control box at Kranji MRT station at 5.46pm that day.

This caused a small fire in the power control box, which was located 20 meters from the station platform, SMRT said in a Facebook post on June 3.

Commuters at Kranji station saw a number of fire engines outside the station and firefighters entering the restricted area of ​​the platform.

The lightning strike also damaged numerous components, especially the disconnect switch in the power control box, causing a power outage, SMRT said.

The surge arrester “did not work as intended” during the MRT outage on June 3

During incidents of transient power surges – such as a lightning strike – a surge arrester is supposed to protect outdoor equipment, according to LTA.

However, on June 3, the surge arrester in the affected power control box “did not function as intended” when lightning struck.

That’s because the part’s condition “could have deteriorated over time,” LTA added:

LTA is working with the operators to review the maintenance frequency of the surge arresters.

The other equipment in the area was not damaged in this incident.

Large crowds formed during the MRT disruption on June 3

Because SMRT engineers had to physically access the power control box on the viaduct, bad weather and lightning risks extended service restoration, LTA said.

Meanwhile, train services could not run. Service on the NSL came to a standstill between Choa Chu Kang and Woodlands stations during the evening peak.

Commuters shared photos of hordes of people stranded outside Yew Tee station, all looking for alternative means of transport.

This also meant that dozens of people in the station had difficulty getting out due to the crowds.

Although free bridge bus services were available, a viral TikTok video showed tempers fraying as a large group of people apparently tried to board a bus, preventing those inside from getting off.

Bridge buses are not a replacement for disrupted rail services: LTA

In its report on the incident, LTA said that bridge buses “cannot be a complete replacement for disrupted rail services”.

That’s because a bus has a capacity of 80 to 120 passengers, while trains can carry up to 1,200 passengers.

While bridge buses play an important role during an MRT disruption, LTA added:

That’s why our longer-term plan is to build the resilience of the rail network with new lines interconnected with existing lines so that most commuters can transfer to an alternative line when a rail line is disrupted.

Maintaining more standby buses entails higher costs: LTA

LTA has taken note of public feedback on what can be improved during future disruptions, the report said.

Specifically, it will assess a suggestion to maintain more standby buses so that they can be activated during an MRT outage.

However, this will “entail higher costs” for the public transport system, LTA said, and so must be “carefully assessed”.

Other improvements that need to be worked on include providing clearer information through public announcements and improving crowd control measures at stations.

June 3 MRT disruption more serious than others in the past two years

Ultimately, the MRT disruption on June 3 was more severe than other major disruptions in the past two years, LTA said.

This was because some of the previous disruptions occurred during off-peak hours. In other cases, train services could also continue to run, albeit at lower speeds.

The service was not fully resumed until 8:10 p.m., more than two hours after the lightning strike.

SMRT said its technicians worked through the night to replace the blown main switch in the control box and fully restore the power system.

Also read: Lightning strike disrupts two-hour MRT service along the North-South Line on June 3

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Featured image from MS News and adapted from Constantine Yan on Facebook.