A giant cavern beneath Barangaroo is about to bridge gaps to greater Sydney

This story is part of an in-depth series investigating the Barangaroo precinct, one of Sydney’s largest urban renewal projects.See all 19 stories.

Sydney’s CBD will be expanded northwards by the completion in 2024 of an $18-billion metro train line that will whisk commuters between a new station, carved out of sandstone at Barangaroo, and North Sydney within three minutes, the rail project’s director says.

With the first driverless train due to pass under Sydney Harbour next year as part of testing, construction of the underground station at Barangaroo is reaching its final stages. Workers are installing a sandstone facade to the station’s walls in a salute to its location near the foot of Barangaroo’s headland park and Observatory Hill, as well as screen doors on platforms for the new metro rail line, high-voltage cables, equipment and systems.

Barangaroo station construction director Claire Moore (left) and Sydney Metro City and Southwest project director Hugh Lawson in an underground cavern.Credit: Wolter Peeters

An above-ground entrance to the new station via escalators and lifts near Nawi Cove – a new inlet cut out of the old container wharf – is intended to be unobtrusive on the surrounding area near the headland.

Sydney Metro City and Southwest project director Hugh Lawson said the three-minute journey to North Sydney by single-deck metro trains would help overcome the natural barrier presented by the harbour, while the new station at Barangaroo would relieve pressure on existing CBD stations.

“It makes it one extended CBD rather than two separated by the harbour,” he said. “It really brings North Sydney into the CBD and shortens those journey times. Heading the other way, [it will be] only about 13 minutes to Sydenham all the way through the rest of the CBD.”

In contrast, a journey on an existing Sydney Trains double-deck service from North Sydney to Wynyard station takes about six minutes. Wynyard provides a link to train services for the southern end of the Barangaroo precinct via a popular underground walkway that opened in 2016.

A station at Barangaroo was listed as only a possibility under early plans for the City and Southwest line, but the government committed to it in 2015 when it allowed the development of larger buildings on the 5.2-hectare Barangaroo Central site, the last of the precinct’s three sections.

Under the original proposal, the line was also to be built above-ground between Chatswood and St Leonards, but plans were later altered so that it would run through tunnels along that section. The City and Southwest line and two other rail projects under construction – a line from the Sydney CBD to Parramatta, and a 23-kilometre link to a new airport in western Sydney – form the country’s biggest public transport investment. On the latest estimates, they will cost $56 billion.

Construction continues at Barangaroo metro station. Credit: Wolter Peeters

From Barangaroo, the City and Southwest line snakes south under the heart of the CBD and on to Sydenham and the final stop at Bankstown in the west.

Perched on the harbour edge, the site of the station is up to 30 metres below ground level at Barangaroo and presented major challenges for builders due to water pressure. The contractor responsible for tunnelling the rail line had to construct a thick concrete wall around the giant hole dug for the station before lining it with a waterproof membrane.

“A lot of the supporting structure [had to be built] inside the primary structure … to just basically hold the box open, so it didn’t try and collapse in on itself,” Lawson said. “We had to drill anchors and poles into the ground to stop the box lifting because we created this buoyant-like structure.”

Thanks to a giant cavern created by a boring machine used to tunnel under the harbour, the station features the only crossover – tracks which cross in an X-shape – on the line between Chatswood and Sydenham. The crossover will allow trains to be turned around if an operational problem occurs on the line, giving the metro line a relief valve to help maintain services.

The Barangaroo station will improve public transport access to the north of the 22-hectare precinct, including the headland, as well as the nearby Walsh Bay Arts Precinct and the Rocks. At present, the northern part of Barangaroo is difficult to get to by public transport.

“What you’ll see is people being able to come from both the south and southwest but also from the north and exit into the city in a very different place,” Sydney Metro chief executive Peter Regan said. “That’s opened up a whole new catchment for the railway.”

The underground track crossover at Barangaroo will be critical in restoring train services if an operational problem occurs on the new line.Credit: Wolter Peeters

Architect and former City of Sydney councillor Philip Thalis agreed that the new station would make Barangaroo and nearby areas much more accessible for a broader proportion of the people of greater Sydney.

“That whole northwestern quadrant is a dead spot in the city, and the metro station is a huge improvement. It means that the arts space at Walsh Bay immediately becomes part of the broader city because it is a long way to walk to get to at the moment from the city,” said Thalis, whose team won an international design competition in 2006 for the waterfront site.

Barangaroo station construction director Claire Moore said a canopy covering a bank of escalators and a pavilion for the lifts to the station below were designed to be “deliberately understated” so that they would blend into the parkland and northern headland.

At other new stations on the line, vital equipment rooms are located on floors above ground level. In contrast, everything at Barangaroo is below ground.

“It is like an iceberg,” Moore said of the underground station. “The majority of what the customer sees is a very small part of the station itself. Everything else is back-of-house – power, station management room, operation rooms, staff meal rooms.”

While the multibillion-dollar rail project is only two years from its scheduled opening, Sydney Metro is yet to put an exact date next year on when the first train will be tested on the line under the harbour to Barangaroo, blaming the pandemic and industrial action for disrupting construction.

“There’s a whole load of things impacting the project at the moment that potentially could delay that,” Lawson said. “You’ll see the stations looking complete [next year] but we’ll be heavily into the testing and commissioning of the railway phase. We can see the end in sight, but we still have to deliver a huge amount of work to get that.”

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