Project Spotlight: City Rail Link (CRL)

City Rail Link

AECOM, Auckland, City Rail Link, CRL, Downer, new zealand, Soletanche Bachy, Tonkin + Taylor, VINCI, WSP,

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City Rail Link (CRL) is a significant $5.493 billion underground railway project in Auckland to improve the city’s rail system by doubling the existing rail network.

The project involves constructing a 3.45 km long twin-tunnel underground rail that will link up to 42 metres below the city centre. Four stations will be redeveloped and built to bring new train station connections.

It will better connect Auckland’s entire rail network and enhance public transport efficiency by doubling the rail capacity and reducing congestion. This railway project will support economic growth and provide a sustainable, efficient travel option for Auckland’s growing population.

Over the next 30 years, a million more people will call Auckland home, so city centre accessibility is crucial for Auckland’s economic growth. Auckland’s rail network is currently at maximum capacity, so City Rail Link will allow its capacity to cope with 54,000 passengers.

City Rail Link is an adapted version of previous proposals to improve the rail network to Auckland’s city centre, with some proposals going back as early as the 1920s.

Major construction work began in September 2019 and is expected to be completed by November 2025.

The design of the rail system was completed by the RCR Tomlinson Opus Joint Venture (SITC Alliance).

In 2019, Link Alliance was awarded the contract to construct all stations and support rail infrastructure. The joint venture comprises Vinci Construction Grands Projects, Downer New Zealand, Soletanche Bachy International N, WSP New Zealand, AECOM New Zealand, and Tonkin + Taylor.

The Cross Rail Link project is jointly funded by the New Zealand Government and the Auckland Council, and its total cost is estimated at $5.493 billion.

Once all construction works are completed, City Rail Link will hand over all stations to KiwiRail and Auckland Transport to carry out the additional required work.

The City Rail Link project in Auckland will feature twin 3.45km rail tunnels, burrowing up to 42m underground between Waitematā Station (Britomart) and Maungawhau Station on the Western Line.

Two new underground stations will open up Auckland’s central city access, including Karanga-a-Hape Station and Te Waihorotiu Station. Entrances will also be constructed at Mercury Lane and Beresford Square.

Both Waitematā Station (Britomart) and Maungawhau Stations will have significant upgrades. Waitematā Station will be redeveloped into a two-way through station, whereas Maungawhau Station will include a new CRL line and a modern station building.

There will also be provision for longer nine-car electric trains and wider network improvements, including The Strand, Ōtāhuhu and Newmarket train stations.

The tunnels were constructed using cut-and-cover and Tunnel Boring Machine (TBM) methods. They varied in depth and were built by installing retaining walls to prevent soil and water from entering the site. The concrete floor, walls, and roof were cast, and the completed structures were backfilled.

A 7m diameter TBM was utilised for the deeper sections of the tunnels. Road headers were employed in areas where the tunnels approached the station box or when they diverged.

When the TBM reached Mayoral Drive, it was disassembled and transported back to Eden Terrace, where it was reassembled to bore the second tunnel.

The tunnels were built directly underneath and through a new retail precinct called Commercial Bay.

The project has received strong support from the public, but its planning and funding have also been controversial. It is projected to cost more than double what was estimated in 2015, with many billions more to be spent across the Auckland rail network in years to come due to cost pressures and design capacity.

Other concerns include project delays, negative impacts on local businesses, environmental and urban implications, and more effective communication and stakeholder engagement.

In September 2023, the New Zealand Infrastructure Commission Te Waihanga released an interim review of Auckland’s City Rail Link (CRL) project. This review was commissioned to provide valuable insights to project teams and decision-makers involved in Auckland Light Rail.

It also offers a reminder of the significant challenges and consequences New Zealand faces when undertaking large infrastructure projects.

While the City Rail Link is a crucial development for Auckland’s future, these concerns reflect the challenges of undertaking large-scale infrastructure projects.

An interim review of Auckland’s City Rail Link (CRL) released

Click here to read the full review.

Maungawhau Station

The Maungawhau Station, where the CRL connects with North Auckland (Western Line), will be redeveloped. Situated near Mount Eden, the new Maungawha Station will feature modern, accessible facilities and advanced technology to improve commuter experience and efficiency. It includes a new modern station building and new and upgraded platforms for the existing Western Line.

The new Maungawhau Station will primarily be accessed from Ruru Street, complemented by pedestrian and cyclist entry points on Mount Eden Road, linking it to nearby active and public transport routes.

Though car parking facilities will not be included, bike parking and accessible pick-up and drop-off zones for private vehicles, taxis, and rideshare services will be available from the station’s primary access. Once complete, it will provide 750 new homes and approximately 20,000 sqm of office space, shops, and restaurants.

Constructing the CRL tunnels from Maungawhau Station

A combination of tunnelling methods was used to build the CRL tunnels from Maungawhau Station. This involved using a tunnel boring machine (TBM), mined tunnelling techniques, and cut-and-cover or top-down tunnel building methods.

Once the tunnel portal is established, trains will transition through the Newton Junction box. This structure is where the 7.5m high TBM transitions into 6m high cut and cover tunnels.

City Rail Link: Maungawhau Station

Karanga-a-Hape Station

The Karanga-a-Hape Station will be a new architecturally designed station just off Karangahape Road, making it easier for people to travel to and within the Karangahape community. The new station will have entrances at Mercury Lane and Beresford Square and is the deepest on the CRL rail network at 33m underground.

The redevelopment of the station will significantly benefit the area by enabling high-density residential growth and urban renewal in the inner-city communities. It will contribute to providing housing stock to help reduce Auckland’s housing shortage over a period of time.

City Rail Link: Karanga-a-Hape Station

Te Waihorotiu Station

The new Te Waihorotiu Station will be expected to be New Zealand’s busiest station after City Rail Link opens to passengers in November 2025. The underground station will be 15m deep and 300m long.

There will be entrances on Wellesley and Victoria Streets (Auckland’s midtown) to revitalise the precinct, provide better access to the area, and create new employment opportunities. 

While structural works are currently being completed underground, redeveloping structures above ground will begin shortly. These works include:

  • Installation of new wider footpath and cycling paths
  • Installation of new road pavement, such as bus stops and loading zones
  • Upgrades of new stormwater infrastructure and other utilities
  • Landscaping works

Once it is in full operation, it will save commuters time travelling to Aotea Centre, Auckland Town Hall, Q Theatre, SkyCity, Auckland Art Gallery, The Civic Theatre and the Central Library.  

Te Waihorotiu Station environmental considerations

A total of 63 trees above the Te Waihorotiu station footprint were removed. This means 13 trees around Te Waihorotiu Station will be replanted, and 40 new trees will be added to the surrounding communities.

For any other trees removed to redevelop or build the other three stations, a new plant will be replaced in the surrounding areas.

Noise mats are also used around excavation and paving works to reduce noise pollution from hydro-excavators and concrete saws. Scrim and hoardings will also be used to minimise any dust effects, and where necessary, water will be used to control dust.

City Rail Link: Te Waihorotiu Station

Waitematā Station (Britomart)

The station at the bottom of Queen Street is being transformed from a dead-ended station into a two-way through station that better connects the city’s rail network.

Waitematā Station (Britomart) has been transformed into a two-way through station to connect Auckland’s rail network better. Twin rail tunnels 14m were built beneath the historic building, Chief Post Office, extending from the current Britomart train station and under lower Queen Street.

Other important construction works included:

  • Modifying and improving existing rail infrastructure within Britomart East junction
  • Raising the west end B2 platform and concourse
  • New equipment, control, and driver accommodation
  • Subsurface infrastructure including relocation of a tunnel wall underneath Britomart Place and strengthening beams

The Waitematā Station is unique to the other three CRL stations as it is considered one of the most complex engineering challenges in New Zealand. This is because transferring the Chief Post Office’s weight onto temporary foundations to protect the historic building during construction was significantly important and challenging.

The station opened in April 2021 after being closed for redevelopment for four years.

City Rail Link’s work on Waitematā Station (Britomart) awarded with ‘Leading As Built’ rating

City Rail Link: Waitematā Station (Britomart)

The City Rail Link project is expected to boost productivity and economic output by $4.229 billion, a significant contribution to the local economy.

Link Alliance also implemented sustainable benefits throughout construction with the ongoing tree planting program and the noise barrier mats. CRL has won outstanding sustainability outcomes on the Waitematā Station (Britomart) and has promised $64m in environmental benefits, reflecting CRL’s commitment to sustainable practices. 

Public transport users will enjoy $138 million in benefits from the improved infrastructure, enhancing overall travel experience and accessibility. This combination of economic, environmental, and user benefits underscores the project’s far-reaching positive impact on Auckland.

In September 2023, Auckland Light Rail completed the end of complex construction around the project’s Maungawhau station site on the North Auckland/Western Line.

In October 2023, the first two 3.45km long tracks for Auckland’s City Rail Link project were laid, connecting Waitematā (Britomart) and Maungawhau stations. City Rail Link’s main contractor, Link Alliance and rail infrastructure company, Martinus New Zealand, started installing the first track in August 2022.

City Rail Link signs a new contract with rail specialist Martinus

Works are underway to build Karanga-a-Hape Station with two entrances in Mercury Lane and Beresford Square.

With the structural construction of the underground Te Waihorotiu Station mostly finished, the focus below ground has shifted to station fit-outs. This involves electrical, communications, ventilation, and safety system installation.

Click here to find out the latest news on the City Rail Link project in Auckland.

Auckland’s City Rail Link project represents a transformative development to enhance New Zealand’s transport system. With extensive economic, environmental, and infrastructural benefits, it represents a forward-thinking investment into Auckland’s future. City Rail Link will be officially completed in November 2025.

Source: City Rail Link 2024

Image Source: City Rail Link (CRL) 2024 | VINCI 2024

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