City Rail Link

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Upgrading Auckland’s metropolitan rail network to reduce travel times and connect communities.

City Rail Link (CRL) is a once-in-a-generation upgrade to Auckland’s metropolitan rail network. Connecting Waitematā Station (Britomart) on the waterfront with the city centre and other key transport links, City Rail Link will reduce travel times and increase public transport capacity, helping residents and tourists access services, homes and businesses across the city and beyond.

This project included the creation of two new underground stations, excavating 3.45 kilometres of tunnels beneath the city, and the redevelopment of Maungawhau and Waitematā (Britomart) Stations. Our team provided independent assurance and oversight to City Rail Link Limited, helping them safely and confidently deliver one of the most complex infrastructure projects ever delivered in New Zealand.

The challenge

Building beneath Auckland’s active city centre involved many challenges, including tunnelling, relocating utilities, and integrating the new infrastructure with their existing rail network.

Maungawhau Station was completely redeveloped, transforming it into a major rail interchange between City Rail Link and the existing network. Two new stations were also constructed to unlock access to new parts of the city. Te Waihorotiu Station is approximately 15 metres below ground and is one of the largest underground spaces in New Zealand. At around 300 metres long, it is expected to quickly become the country’s busiest railway station. Karanga-a-Hape Station presented different challenges: constructed 33 metres below ground, it will be the deepest railway station in New Zealand.

Beyond the stations, the project involved the installation and integration of numerous complex systems, including track, signalling, traction power, ventilation, fire life safety, building management and communications systems. These systems and subsystems, alongside thousands of other assets, all needed to work together as one – ensuring smooth operation of the railway in normal, degraded and emergency situations. This required careful testing, coordination, technical scrutiny and robust assurance documentation.

Our role

From 2018, we supported City Rail Link Limited as Independent Safety Assessor, providing an independent objective assessment of the project’s safety management, safety engineering and assurance arrangements from design and construction through to testing, commissioning and final approvals to enter passenger operations. In 2023, our role expanded with our appointment as Independent Certifier, ensuring that the as delivered infrastructure and assets achieved the client’s end state requirements.

By identifying gaps and recurring issues early through regular audits and end-to-end traceability checks, we helped the project proactively manage risk and prevent issues affecting later stages.

Our stage reports, safety stage gate presentations and regular attendance at project forums translated detailed findings into clear, decision-ready insight for the client, delivery teams, key stakeholders and the rail regulator. A shared Power BI dashboard gave stakeholders transparent, up-to-date visibility of observations and actions. And when programme pressure intensified, we mobilised specialist expertise from across our global network to accelerate reviews without compromising the rigour of our assessment.

This consistent, collaborative approach helped build confidence in the evidence, supported informed safety decisions and kept the programme moving towards passenger operations.

The impact

City Rail Link will unlock greater capacity across Auckland’s rail network, improving access to jobs, education, services, and recreational opportunities across Auckland. Faster and more frequent rail services will connect more people to the city centre and key destinations, reducing travel times and making public transport a more attractive and accessible option for residents and tourists alike.

The project will also support urban regeneration, creating walkable, liveable and vibrant communities around the new stations and reducing congestion.

City Rail Link has generated thousands of jobs and training opportunities, including targeted pathways for Māori, Pasifika, and young people in the region. In addition, more than NZ$150 million was directed to Māori and Pasifika businesses, helping strengthen local enterprise and community prosperity. Mana whenua partnership shaped the project throughout: the four station names were gifted by CRL Ltd’s Mana Whenua Forum and formally adopted through the New Zealand Geographic Board Ngā Pou Taunaha o Aotearoa, and mana whenua artists’ work is integrated into every station.

Our work helped ensure safety and reliability of the new systems and stations – providing independent oversight, technical assurance and confidence across one of the most complex infrastructure programmes ever delivered in New Zealand.