The tough task threading a train line through Sydney’s crown jewel

A driverless train will snake its way under Sydney Harbour and the central city for the first time next year, passing new underground platforms and concourses chiselled out of sandstone beneath Central Station as testing begins on the state government’s flagship metro rail line.

Underscoring the challenges facing engineers, much of the rejuvenation of Central – the crown jewel in Sydney’s fast-growing rail network – has been taking place only several metres below suburban rail platforms where tens of thousands of commuters get on and off trains every day.

Escalators and lifts will link suburban platforms to the Central Walk concourse.Credit: Janie Barrett

Within the next six months, passengers will begin streaming through the first part of an underground concourse known as Central Walk.

Creating a spine for the station, Central Walk will be a distribution point for commuters switching between suburban rail platforms, intercity and regional trains, light rail and, by 2024, fully automated metro trains.

Commuters have already had a taste of the biggest upgrade in decades of Australia’s busiest station, which has been spurred by the construction of the City and Southwest metro rail line.

Housed under a roof shaped like a hockey stick, work on a concourse at the northern end of Central was completed recently, increasing space and natural light, and revealing parts of the station’s sandstone exterior hidden from view for decades.

Sydney Metro City and Southwest project director Hugh Lawson said upgrading a station used by hundreds of thousands of people every day had posed significant challenges.

“Everything was amplified to the maximum. The challenges are more complex,” he said. “We have built this right in the middle of Central Station while it’s been operating.”

The upgrade helps remove a rabbit warren of passages and gives a sense of space due in part to higher roofs of the new concourses. At the northern end, Central’s clock tower reveals itself to commuters through large louvres.

Sydney Metro City and Southwest project director Hugh Lawson.Credit: Janie Barrett

With testing of automated trains expected to begin next year, Mr Lawson said Central was the most advanced of the stations along the new metro rail line in terms of “looking like the finished product”.

“Central Walk takes a lot of pressure off those old pinch points because suddenly people will be able to interchange through a much easier route,” he said. “For people using the suburban platforms, it will change their journey, even if they’re not a metro customer.”

From platforms for suburban rail lines, commuters will soon be able to take escalators or lifts to the Central Walk concourse.

And once the City and Southwest rail line opens in two years, they will take another set of escalators from Central Walk to reach platforms for the new metro trains about 37 metres below the surface. Screen doors are due to be installed on the 270-metre-long metro platforms in the coming months as the project reaches its final stretch.

The 45-metre escalators connecting Central Walk to the metro rail platforms are billed as the longest in the southern hemisphere. However, they are still a far cry from the world’s longest, which extend for 138 metres at railway stations in St Petersburg in Russia.

Sydney Metro associate director of design Connie Klonis said the station would become much easier to navigate. “Before, when you were walking through Central, it was quite difficult to orientate yourself because everything was so enclosed,” she said.

To create the new concourses and metro platforms, British contractor Laing O’Rourke has excavated more than 375,000 tonnes of sandstone from beneath Central Station over the past three years. A bridge had to be built over rail tracks to allow trucks to access the site.

Construction manager Oisin Farrell said the excavation for Central Walk had been carried out without passengers standing on platforms above knowing about it. “We’ve excavated and done our structural works all underneath a live track, all while the trains are running. The suburban platforms are the busiest platforms in all of Australia,” he said.

About 250,000 people a day pass through Central, and the number is forecast to increase to 450,000 by 2036.

NSW Transport Minister David Elliott said the upgrade would take pressure off other City Circle stations by providing commuters better access to other transport modes such as light rail and buses.

“It delivers a Central Station that will help commuters travel around this great city for decades to come,” he said.

The City and Southwest line is the first under central Sydney since the construction of the Eastern Suburbs line in the 1970s, and forms the second stage of the city’s emerging metro rail network. The Metro West rail line, which is the city’s biggest rail project and will extend from central Sydney to Parramatta, is due to be completed by 2030 at a cost of up to $26.6 billion.

Work on the northern concourse at Central Station was completed recently.Credit: Janie Barrett

The Herald recently revealed that the cost of the City and Southwest rail line is running billions of dollars over budget. Tender documents show the cost of the Central Station upgrade has increased by $185 million to $1.14 billion.

Sydney Metro, the government agency managing the rail project, has said that construction market on Australia’s east coast is the “hottest it has ever been”, and every major construction project around the world faced challenges with demands for labour and materials.

Mr Lawson, who worked on London’s suburban rail network before joining Sydney Metro five years ago, said the pandemic had been a “big hindrance” to the project over the past two years.

It reached a head in July last year when construction across greater Sydney was shut to contain the spread of COVID-19. “We were at peak delivery going into that construction pause,” he said.

“The restrictions carried on for quite a long time. People weren’t able to move freely to come to our sites, even if the sites were open.”

With more of the upgraded parts of Central to be opened shortly, architect and urban planner Philip Thalis said the width, height and other dimensions of the new concourses were a “real plus”, creating clear lines of sight to help commuters navigate the station.

“They are building public works for a metropolis, and that is what we should be doing. We need public works commensurate with the crowds,” he said.

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