Complex works, tough terrain: Building Jurong Region Line no easy task

SINGAPORE – For years, motorists driving on the PIE watched large concrete columns rising near the highway as the groundwork was laid for the new Jurong Region Line (JRL).

Trains will start running in about two years on what will be the country’s seventh MRT line, but getting the viaducts built was no simple task.

It meant construction crews working in the dead of night in four-hour blocks, when traffic becomes light and roads can be closed.

The 24km JRL is the first MRT line to be built entirely above ground. The North-South and East-West lines have a mix of above-ground and underground sections.

The JRL was unveiled in the 2013 Land Transport Master Plan, when plans were taking shape to transform the western region with new homes and employment centres. It was first announced in 2001 as a light rail system.

When completed, it will have 25 stations and three interchanges – in Choa Chu Kang, Boon Lay and Jurong East. The station names will be made known later.

The JRL will provide transport links to people living in Choa Chu Kang, Boon Lay and Tengah, and improve access to the Jurong Innovation District, Jurong Lake District and Nanyang Technological University.

Today, Stage 1 is about 80 per cent complete, the Land Transport Authority (LTA) told The Straits Times.

Structural works at all 10 stations and their viaducts have been completed, while electrical and mechanical installations, architectural finishes and external works are moving along.

The JRL will be a medium-capacity line, with smaller three-car trains that can navigate tighter curves through built-up areas. There is an option to add a fourth car in future if demand goes up.

The decision to build an above-ground line meant there were a few construction challenges – and made the works particularly visible to residents, with viaducts and stations taking shape right outside some homes, bringing years of noise, dust and disruption to their doorstep.

Mechanical engineer Ameer Kaisar Ali, 55, who lives in Block 234 Jurong East Street 21 overlooking the future JE4 station, said the noise from the construction work is constantly in the background when he is home.

He said: “We are experiencing a lot of noise all the time. Twenty-four hours, it’s noisy.” He added that the flat needs sweeping daily because there is “such a huge amount of dust”.

But Ameer said he understands that the construction work is necessary.

“I’m an engineer, so I understand the situation. This spot is very sensitive… That’s the reason we are patient,” he added.

Boon Lay resident Tze Lin, 36, who works nearby in Joo Koon, said travelling around the western region – where many of her family members live – will become a lot more convenient once the JRL opens.

But noise and bright lights from the construction site at night have irked her family. “I don’t think the windows are soundproof,” she said.

A few residents said all the inconveniences will be worth it when the JRL is completed.

Purchasing manager Lay Ching Ong, 48, who lives in Jurong West, said it will likely take about five minutes to walk to the future JS5 station from her home. Now, it takes her about 20 minutes or more to walk to Lakeside MRT station.

The JRL, she added, will make it easier for her to go to her office in Tanjong Pagar.

Heavy lifting

The JRL will cross over the AYE and PIE at five places.

Construction crews cannot easily close the lanes on the PIE during the day and lift into place the huge concrete sections needed for building works. What they get is a short window at night.

Project director Phua Hooi Leng said lane closures usually start at about 11pm. Segment launching takes place between 1am and 3am, with the works completed and lanes reopened by 5am – in time for the first buses to pass through.

At one section near the Jurong East Flyover, an existing 7.4m-wide open canal also ruled out the conventional method of lifting viaduct segments vertically.

Engineers designed a special lifting frame to lift and slide the segments into position instead, said Phua, who is an engineer.

The construction of the viaducts is also a challenge.

Phua said elevated viaducts are built by first installing deep foundation piles, which can extend up to 40m underground.

Precast concrete segments, each weighing up to 120 tonnes, are then lifted and connected between piers using high-strength steel cables. This allows the structures to be built efficiently while maintaining precise alignment for safe train travel in densely built areas.

Eleven precast yards were set up, mainly in Tengah and Tuas, to manufacture all the viaduct segments.

At the AYE crossing, the Teban Flyover had to be fully closed in both directions while segments were hoisted from ground level and moved across to the opposite pier.

The work also had to be completed within a four-hour window, from 1am to 5am.

Building above, under and around

Among the most complicated construction sites is near Jurong Hill, where the JRL viaduct goes over an existing flyover.

Below it, there is a road as well as an underpass – making it a four-layer intersection.

Running underground is a dense channel of critical utility lines serving Jurong Island, including telecoms cables, water mains and high-voltage power cables.

That means construction must be done above, below and around the utility lines.

Some utility lines needed to be diverted and roads temporarily realigned, said Phua. When the utility lines cannot be moved, steps must be taken to make sure no damage is done.

The construction team also used tools like tiltmeters, vibration sensors, settlement markers and real-time 3D prisms to monitor nearby buildings and structures, he said. Readings are recorded daily so that steps can be taken if any abnormal movement of the buildings and structures is detected.

In Jurong East, the JRL viaduct crosses over the East-West Line, and safety concerns meant the usual way of lifting a precast concrete segment vertically from the ground would not work.

The segments can each weigh up to 120 tonnes, and a 1,700-tonne crawler crane – one of the largest cranes on land in Singapore – was brought in for the lifting works.

Construction crews had to wait for engineering hours, approximately between 1.30am and 4am, to begin work, after the last passenger train had returned to the depot and engineering trains gave the green light.

Finding space

Much of the JRL runs through built-up areas like Choa Chu Kang, Jurong, Pioneer and Tengah.

At one section in Jurong East, the gap between the JRL track and the fully running North-South Line’s viaduct is only about 1m.

That is why the line’s trains were designed to be smaller and more manoeuvrable, and why the same constraints shape the way the train line is being built.

Where the alignment is straight or gently curved, launching girders – a special type of crane that is up to 150m long and weighs more than 300 tonnes – can be used.

Then there are ground conditions to consider.

The JRL is being built largely over sedimentary rock formations, but ground cavities in some spots needed more reinforcement, said Phua.

Before a viaduct could be built over a 25m-wide canal in Jurong West, for example, ground improvement works had to be done to strengthen the soil before heavy equipment could be deployed.

Almost at the finish line

Construction of the JRL started in January 2023, after more than three years of preparation.

At the time, LTA estimated that the line would open in three stages between 2027 and 2029, with an expected daily ridership of about 200,000 that can rise to more than 500,000 as Tengah town, the Jurong Innovation District and Jurong Lake District grow.

More than 60,000 additional homes were expected to be within a 10-minute walk to a train station when the line is completed.

In March, then Acting Transport Minister Jeffrey Siow, speaking in Parliament, said the opening of the JRL is delayed by six months to the middle of 2028 due to construction delays and testing.

The first stage – comprising 10 stations linking Choa Chu Kang to Boon Lay and Tawas off Jalan Bahar – was slated to open by end-2026.

It was delayed by a year because of the Covid-19 pandemic and pushed back another six months to mid-2028 in March because of construction delays and testing requirements.

On Sept 20, Siow said shuttle services that shadow the JRL route will be rolled out until the trains start running. The shuttle services will start from the second half of 2027, and take commuters to key stations.

The complexity of building an entirely elevated line in a densely populated area contributed to the delays. For example, construction over the 25m-wide canal required more extensive ground preparation than what was initially planned.

The JRL will open in three stages, with Stage 1 expected now to start running from mid-2028.

LTA said it would provide updates on Stages 2 and 3 as work progresses. Stage 2, from Tengah to Pandan Reservoir, is currently slated to open in 2028. Stage 3, which will extend the JRL into Nanyang Technological University and towards Jurong Pier, is currently expected to open in 2029.

The new line will provide alternative routes for Choa Chu Kang and Boon Lay residents and help redistribute passenger loads on the existing network. It is also part of efforts to support the west’s transformation into a major residential and employment centre.

While 24 stations were originally planned for the line, a new station, JS2A in Tengah, is now being built between Choa Chu Kang and Tengah to serve future residents of the Forest Hill district. This will bring the total number of stations to 25.

The trains will be fully automated and driverless. They will also have three wide doors on each side of every car, each 1.5m wide, wider than those on existing MRT lines. Each car will have space for wheelchair users and strollers.

Compared with trains on other MRT lines, JRL train cars will be smaller to better navigate built-up areas.

Five of the 62 JRL trains have arrived in Singapore so far, LTA said.

The JRL will also be the first MRT line to operate under a new rail contracting model marked by a joint venture between SBS Transit and French transport firm RATP Dev. The venture won a nine-year operating contract in 2024, with the option of a two-year extension.

The service fee quoted by SBS Transit and RATP Dev Asia-Pacific to operate the line for 11 years came to about $750 million.

For commuters, the JRL will be a key node that will connect them to the larger Singapore transport network.

Building it, however, was far from straightforward. Challenging situations were met with innovative decisions, and soon, it will be an engineering feat that will serve Singaporeans well.