How does S’pore build our MRT tracks?

Deep down in a busy underground space

| Janice Seah | Sponsored | December 06, 2022, 12:02 PM

We’ve all dreamed of the day we can just walk out of wherever we are, hop onto an MRT train and get to our destinations, be they our homes, offices or schools, in a shorter time. Well, dear commuter, while the day has not quite arrived, it is, much like the next train, definitely on its way.

And if Land Transport Authority’s (LTA) Senior Group Director, Rail, Ng Kee Nam has anything to say about it, it will come sooner rather than later.

Ng Kee Nam, Senior Group Director, Rail at Land Transport Authority

Ng is the man at the helm of the LTA Rail Group, tasked with bringing parts of the Land Transport Master Plan (LTMP) 2040 to fruition. The goal is to increase the network by 50 per cent, bringing it from around 260km today to around 360km by the 2030s. 

The 64-year-old veteran, who has been with the LTA from its incorporation as the Mass Rapid Transport Corporation in 1984, has seen the system grow from the first five stations in 1987 to where it is today - a whopping 200 MRT and Light Rail Transit (LRT) stations, across six MRT and two LRT lines. 

The first Singapore MRT station topping out ceremony at Toa Payoh MRT station in 1985

Speaking with an almost fatherly pride, Ng said: “It’s been 35 years, and I can still vividly remember the day of the first major milestone of our MRT journey, when we commenced service from Yio Chu Kang to Toa Payoh.

“We have learned and grown much since. At that time, some journeys were very long and inconvenient. While we still face challenges today, we have come a long way in bringing our passengers to their destination.

“But we think we can do more. We want to bring the network even closer to more households. That’s our plan.”

To infinity and beyond (well, almost)

That’s the plan: by walking, cycling, or taking the public transport, you can reach your nearest neighbourhood centre within 20 minutes or take no more than 45 minutes to complete most peak-period journeys to reach your workplace.

The Cross Island Line which is slated to be completed by the early 2030s will indeed link the west coast of Singapore to the east coast in one grand swathe of track and trains. 

Until then there are other milestones to celebrate. The third stage of the Thomson-East Coast Line (TEL), one of the world's longest driverless rapid transit lines, opened last month on the 13th, reducing travel time from Woodlands South to Orchard from 50 minutes (by bus and MRT) to 35 minutes (MRT alone).

Sacrifice: Painful but necessary. 

Ng recognises that while constructing these stations, there has been some inconvenience to the public, who put up with congestion, noise, dust and detours.

There is also a general feeling that Singapore is in a constant and never-ending state of construction everywhere you go.

“LTA is mindful of the inconveniences that Singaporeans have to live with, and we are thankful for the general graciousness that Singaporeans have shown while we work to enhance the network,” he said, adding that the team engages stakeholders regularly and strives to minimise the inconveniences where possible. 

“We try our best to address these inconveniences and concerns. For example, we carry out project environmental studies to mitigate inconveniences like dust and noise. We also put up protective hoardings and noise barriers and of course, keep safety paramount at all times.”

Finally, he advocated taking a “big picture” view of things. “These inconveniences are temporary. The cooperation between us and the community and various stakeholders eventually bears fruits – in the form of a new station that will benefit everyone for decades to come.”

“For example, some people may say that having the TEL is good enough. However, with the development of the Changi industrial area, there is a need for better East-West connectivity, hence the development of the Cross Island Line.”

Deeper stations and more complex processes

The optimisation of land use is paramount in land scarce Singapore, and is one of the key considerations in the planning of all rail lines. Where suitable and appropriate, lines will be built fully underground so that land utilisation for future developments around the rapid transit system can be maximised. 

“Constructing underground takes more time; and there are many more challenges like the diversion of water, power, sewage services before we can start constructing the stations.

Even as we construct, we must ensure that these services are not disrupted for the stakeholders,” said Ng. 

“All this foundation work takes a lot of time to plan, design and execute and we often face various challenges behind the scenes. But it is vital that it is done and done right.”

“The time taken for construction takes into account the scale and complexity of each project. It depends on site conditions, ground conditions and how developed the land above the station is and involves a huge number of people.”

Given the depth some of these stations go to (the Bencoolen station, at 43 metres below ground, equivalent to 14 storeys underground, is currently the deepest one in Singapore), and we are going deeper as the network gets intensified. It’s only natural to wonder how one gets work done in such conditions.

A cool way to build

Cutting edge technology is key in making the parts come together. Ground freezing, (a centuries-old technique updated for the 21st century) was used in the construction of the Thomson-East Coast Line Marina Bay station. It stabilises soil to prevent it from collapsing next to excavations and turns water to ice so as to prevent ingress into the site. Pipes are run through the soil and then filled with refrigerants which freeze the soil. 

“The frozen soil,” Ng said, “becomes an impermeable wall of ice, sometimes as hard as concrete.”

The use of rectangular tunnel boring machines instead of conventional cut-and-cover methods, which would have required traffic and utility diversions, also paid rich dividends as it saved on manpower and boosted productivity by an estimated 30 per cent.

This was the method used to build the Stevens underpass and led directly to it being completed two years ahead of schedule - a particularly satisfying feat for Ng and his team.

Cross-section depiction of ground freezing process performed at Marina Bay Station to stabilise ground conditions and facilitate tunnel construction for TEL3

This accomplishment feeds into Singapore’s overall vision to shift towards more environmentally friendly forms of commuting - such as trains, buses, bicycles and good, old-fashioned walking. 

A cycling path network that is more than double the current size - from around 500km now to 1,300km by 2030, is also on the horizon.

Ng addressed the all-too-familiar gripe about service breakdowns, which at one stage plagued the system. He said that while “things can go wrong”, the LTA has strived to contain the train faults. 

“The target set to improve rail reliability was to achieve a million Mean Kilometres Between Failures. I’m glad we’ve exceeded our target. It is stressful but we think it is important that we do our best” Ng smiled.

It’s a vision as grand as it is painstaking, as far-reaching as it is tantalising - to take public transport in Singapore to the next level. Ng added that LTA is also grooming the next generation of LTA leaders to write that chapter and achieve the vision.

This is a sponsored article by the Ministry of Transport.

All photos via MOT.