The client, City Rail Link Ltd. (Auckland Council and NZ Government), are seeking to provide an integrated public transport network aimed at cutting travel times, easing congestion and reducing pressure on the existing bus system.

CRL is a 3.45 km twin-tunnel underground rail link running up to 42 metres below Auckland's city centre. As the first completely underground railway line in New Zealand, it will transform the downtown Britomart Transport Centre into a two-way through-station, ensuring better connections with Auckland's rail network.

The team has embraced and enhanced the Infrastructure Sustainability Council of Australia (ISCA) Infrastructure Sustainability (IS) rating framework, working with Mana Whenua to make it more appropriate for the New Zealand context. This has involved utilizing the project’s digital twin, which has been modelled using BIM, to track the embodied carbon and CO2 emission reduction targets as design and decision making Progresses.

WSP takes pride in the fact that this project has brought professional development and a technological shift not only to the Link Alliance, but also to New Zealand's entire construction sector.

CRL is not just the sum of its many parts, rather it needs to be a fully operational railway system. Moving people around the city requires the integration of complex station building systems and rail systems, such as signalling and overhead power feed, to provide a safe and reliable service.

In addition to the design, construction and installation of those parts, the systems need to be integrated, tested, commissioned to demonstrate thousands of requirements. Training of drivers and operators is then required to allow the system to be proven by trial running before the system is accepted and trains can enter service.

One of the notable features of the CRL project is its advanced use of digital technology. WSP is leading the implementation of Geographic Information System (GIS) and Building Information Modelling/3D (BIM/3D) to the Issue for Construction stage of works to integrate CRL designs seamlessly across teams.

We’ve used BIM to deliver key components of this project including:

• Computational tunnel design and modelling
• Comprehensive work breakdown
• Tracking of interdisciplinary design issues
• Automated quality assurance reports
• Optimisation of tunnel boring machine operations
• Simulations for customer and operators’ experiences
• Effective Management of asset information

Leveraging BIM, we significantly reduced project downtime and seamlessly transitioned to remote work amid the COVID-19 pandemic. This innovative approach earned the Link Alliance the Excellence Award at Autodesk's Architecture, Engineering, and Construction (AEC) Awards.

WSP are part of a dedicated team responsible for integrating sustainability and carbon reduction measures directly into CRL's design processes.

Our combined goal as an alliance is to reduce embodied carbon by 15% and overall construction and operational emissions by 25%.

To help achieve this, we’ve adopted the Infrastructure Sustainability Council’s rating framework to assess, enhance, and validate sustainability performance.

These initiatives have set industry-leading benchmarks, notably earning the CRL the Infrastructure Sustainability Council (ISC)'s Excellence in Design certification in 2020 — a first for any project in New Zealand.

Our behavioural science team, part of WSP's research division, draws on a deep understanding of human interactions with the built environment. By considering a range of user abilities and challenges, they enhanced our insights into design and functionality of public and operational areas.

Link Alliance called on our team to collaborate with operators and users to help improve the CRL design by making it intuitive and easy to understand.

They developed simulations with Building Information Modelling (BIM) models to test different safety scenarios, including normal operations, degraded conditions, and emergencies, involving passengers, drivers, and system operators.

In 2012, Mana Whenua were formally integrated into the City Rail Link project through a dedicated forum comprising of eight iwi members.

The forum meets monthly and take on roles including on design, contributing to plans, collaborating on heritage matters, fulfilling kaitiakitanga (guardianship) responsibilities, and choosing station names.

By bringing in Mana Whenua at the beginning of the project, Link Alliance was able to facilitate a meaningful space to engage and kōrero (discuss) project solutions, community, and social outcomes, and ensuring a successful outcome for everyone involved.

City Rail Link Ltd., and Link Alliance habr worked collaboratively with eight mana whenua iwi to embed cultural narratives within the design of the CRL.

At the core of the architectural and urban design for the CRL lies the embodiment of the Māori Creation Story, conveyed through four expansive elements.

The earth element symbolizing Papatūānuku, or Mother Earth; the sky element representing Ranginui, or Father Sky; the threshold element portraying each station's atua (deity); and the fourth element embodying the glimmer of dawn.

At both Te Waihorotiu and Karanga-a-Hape stations, the earth element is displayed through incorporation of precast panels that emerge from the ground which depict Waitematā sandstone. The panels' colour and texture harmonise with the surrounding Waitematā sandstone in Auckland harbour.

Within Te Waihorotiu Station’s Wellesley Street entrance, the threshold element is located above the ticket gates. The artwork recreates the flowing stream of Wai Horotiu (Horotiu stream which sits under Queen Street) with water passing through a sea of reeds towards Waitematā harbour. Ripples can be seen from outside the station flowing into the main entrance. At the centre of the reeds rests Horotiu, a kaitiaki and mythical spirit and guardian of the Horotiu stream.