Featured, From the magazine, New Zealand, News, Newsletter, Transport, Tunnelling

City Rail Link delivering on Auckland’s public transport needs

City Rail Link

The largest transport infrastructure project in New Zealand’s history, the City Rail Link project is doubling the capacity of Auckland’s rail network.

What is the City Rail Link?
The City Rail Link (CRL) project is a huge project with an equally huge impact on the growth of the city of Auckland and its future prosperity. The CRL is a 3.45 km twin-tunnel underground rail link up to 42 m below the Auckland city centre. The goal of the project is to transform the downtown Waitematā Station (Britomart) into a two-way through-station that better connects the city’s rail network.

The tunnels will connect Britomart with a re-developed Mt Eden station on the western line. Additionally, two new underground stations, Karanga a Hape and Aotea, will open central city access.

The project allows the rail network to have at least double rail capacity.

An ambitious $4.4 billion project, the CRL will double the number of people within 30 minutes of central Auckland which is the country’s largest employment hub. When fully operational 54,000 passengers an hour will use CRL stations at peak hours. This is the rail equivalent of an additional 16 lanes of road or three Auckland Harbour Bridges.

City Rail Link
The City Rail Link is the largest transport infrastructure project in Auckland’s history.

A brief history of the CRL
Moves to create an underground rail system in Auckland go back almost a hundred years – beginning in the 1920’s.

In 1923 the then Railways Minister, Gordon Coates, granted his support for a city-to-Morningside underground rail line. ‘The Morningside Deviation’, as it was then known, was to be an underground tunnel from the CBD to Morningside.

Envisaged was a rail link between the main trunk line station on Beach Road, underneath the central business district with a station near the Auckland Town Hall.

The cost of the project was estimated to be around £400,000. An equivalent today of approximately $45,934,199 New Zealand dollars.

Several years later, in 1930 the proposal was rejected, and the main terminal relocated to Beach Road. Nevertheless, references to a Morningside deviation continued to arise – in 1937 there was further discussion regarding the plan to reduce unemployment.

In the 1940s, the Ministry of Works released an expansive rail plan for Auckland, refining the Morningside proposal. The report discussed electrification, proposed an underground inner-city loop and an overground suburban western loop.

In the end, Wellington’s rail was electrified not Auckland’s.

In 1955-1956, Auckland City Council moved to embrace the advancement of motorways and ordered a Master Transportation Plan to decide the rail versus motorway issue.

The plan considered the Auckland Morningside deviation, which was to take a similar yet not wholly identical, route to the 1928/29 plan. An investigation of buildings along the proposed route was undertaken, looking at their condition, type of foundation and value.

The plan recommended a massive increase in motorway construction at the expense of rail. It was argued, at the time, that buses could use motorways making rail unnecessary.

Near the beginning of the new millennium, the Auckland Regional Authority once more revived the push for the electrification and expansion of a passenger rail network. The push was spearheaded and championed by the authority’s chair and long-time public transport advocate, Mike Lee.

In 1993, 19 second-hand railcars were delivered from Perth as an interim measure. 

Several years later, in 2009, KiwiRail and Auckland’s Regional Transport Agency (ARTA) announced it would begin a detailed study into the possibility of an underground route that would link the Britomart rail terminal with the Mount Eden railway station.

The cost of a twin-track tunnel was estimated to be more than $1 billion.

Electrification was announced as a major plan by the Labour government in May 2007 and confirmed two years later by a National government in 2009.

Following the 10-year anniversary of the opening of the Britomart Transportation Centre, Auckland Council announced that it was in discussions to build a section of tunnel under the Downtown Shopping Centre during a redevelopment planned for 2016-2017. 

On 1 August 2014, Auckland Transport announced a significant design change to the project, dropping the underground Newton Station in favour of a significant upgrade to Mount Eden station. 

Ultimately, this change would save construction costs approximately $124 million, require fewer properties to be bought by Auckland Transport and, in the long term, save operational costs. In addition, the change would allow for Mount Eden station to be connected to the CRL, which previously bypassed it, and would separate the east–west junctions, meaning that rail lines would not cross one another. 

In May 2015, electric trains began to run on all of Auckland’s lines.

Since the electrification of the train line, Auckland’s public transport has begun to enjoy somewhat of a renaissance that shows no signs of stopping just yet.

In recent years, the New Zealand government has understood the importance of transport equality. Subsequently, in 2016 the Prime Minister at the time John Key announced that central government funding for main works construction of the CRL had been confirmed and that the Auckland Council had been granted the green light to begin construction of main works in 2018.

A year later, Finance Minister Steven Joyce and Transport Minister Simon Bridges signed agreements with Auckland Mayor Phil Goff that established City Rail Link Limited (CRLL). Effective as of July that same year, the company assumed responsibility for delivering the CRL project.

Auckland’s biggest infrastructure project begins construction
The City Rail Link tunnels have been constructed using both cut-and-cover and tunnel boring machine (TBM) methods depending on the location and requirements of construction. The ground through which the tunnels are built vary between firm rock and soft soil and, likewise differs in depth to natural ground level between 40 m and 0 m.

The project officially began its early works package in October of 2015 between Britomart and Wyndham Street. 

Working since December 2015, the Connectus – a joint venture consisting of McConnell Dowell and Downer – installed 362 reinforced concrete piles around the future CRL twin tunnels.

CRL Chief Executive Dr Sean Sweeney noted that construction undertaken in the middle of a thriving city such as Auckland is never easy, but that the CRL took a big step toward establishing itself as a project that will change the way people can travel throughout the city. 

Flashing forward, the CRL’s Dame Whina Cooper TBM – named after the inspirational Māori rights activist Dame Whina Cooper – reached the milestone of 500 m bored in late 2021.

Dame Whina Cooper began tunnelling CRL’s southbound tunnel in late May earlier that year. With works having been restricted by COVID-19, the TBM continued to operate at low capacity during the five-week lockdown to reduce the risk of becoming stuck. Nevertheless, Dame Whina managed to complete its first 860 m leg from the Mt Eden site to Karangahape in October 2021 despite the restrictions and difficulties.

On 10 November 2021, the Dame Whina Cooper TBM began the second leg of its four-stage journey below the Auckland streets. 

The TBM’s 785 m venture from Aotea Station concluded early in the new year and saw Dame Whina dismantled underground before being returned to Mt Eden in sections, reassembled and then ready to excavate the second rail tunnel in 2022.

Throughout 2022, works continued to ramp up on the CRL. 

The TBM continued to power away beneath NZ’s surface, excavating the second 3.45 km underground rail tunnel and removing dirt and rocks to the surface. However, the TBM was doing more than just excavation.

The machine had also been busy installing precast concrete panels to line the tunnel walls.

Upon reaching its destination in September, the TBM had travelled 840 m from the Link Alliance Maungawhau (Mt Eden) Station construction site, placed 519 segment rings and removed 74,000 tonnes of soil.

City Rail Link
A landmark achievement, the City Rail Link project has proved New Zealand’s infrastructure capacity to take on such a large and innovative project.

A future just unfolding – what comes next for the CRL?
Since the beginning of the CRL project, more than 2000 jobs have been created, the complexity and innovation of which has upskilled the workforce and will continue to benefit future generations long after the project is completed.

Now that the twin 3.45 km tunnels have been built, the next stage of the project is primed to commence: installing the tunnels with tracks and necessary rail systems required to convert them to rail use.

Building an underground rail network has never been attempted in New Zealand before and to have achieved what the CRL project team has in the face of a global pandemic, multiple lockdowns, restricted working conditions and a myriad of other challenges is a remarkable feat.

Though the project is far from completion, the final breakthrough of the TBM and the completion of digging the final tunnel is an achievement not to be taken lightly. The project has seen the Dame Whina Cooper TBM travel more than 3.5 km, place 1067 segment rings and remove 130,000 tonnes of soil during the boring of the twin tunnels. The project likewise saw more than 64,200 cubic m of concrete was used to build the CRL tunnels which is equivalent to 25 Olympic sized swimming pools.

“There is so much more to do on the CRL project, but the final breakthrough is an appropriate moment to pause and reflect on the extraordinary job our people have done in building these twin underground tunnels,” Dr Sweeney says, reflecting on the reaching the major milestone. 

“These tunnels are the cornerstone of the country’s first rapid transit rail network and will enable a transformational change in our biggest city.”

Upon completion of the project, Auckland’s rail network will be granted at least double the rail capacity and will be primed to provide efficient public transportation across the city of Auckland. A landmark achievement, the project has proved New Zealand’s infrastructure capacity to take on such a large and innovative project.

For more information visit CRL.

Subscribe to Trenchless Australasia for the latest project and industry news.


This article appeared in the October edition of Trenchless Australasia. Access the digital copy of the magazine here.

Previous ArticleNext Article