CityRail Link is a 3.4-kilometere extension to the existing Auckland Rail Network, connecting Britomart Station to Mt Eden Station through Auckland's West. The extension is made up of twin tunnels that will connect downtown at Waitematā Station (Britomart) with Maungawhau on the Western Line.
The scope of the project includes:
- construction of a one-kilometre Cut and Cover Tunnel
- construction of 2.5 kilometres of Bored tunnel
- redevelopment of Waitemata Station and Mount Eden Station to accomodate below ground rail lines, and
- construction of two new underground stations, Te Waihorotiu Station at a depth of 13 meters and Karanahape Station at a depth of 33 metres.
Procurement has been divided into stages, with the largest 'C3 Stations and Tunnels' package to be delivered through an Alliance Contract. Originally there were nine contracts envisioned - however, reshuffling of scopes of work has left the project with the following contracts:
- Contract One (C1), delivered by Downer Soletanche Bachy Joint Venture: construction of the initial sections of the CRL tunnels from Waitematā Station (Britomart) to the Downtown Shopping Centre, and refurbishment of the Chief Post Office (CPO) heritage building. Completed in October 2021.
- Contract Two (C2), delivered by Connectus, a McConnell Dowell and Downer Joint Venture: 350 metres of trenching and tunnelling from Commercial Bay at Customs Street to Wyndham Street, relocating a stormwater main, strengthening the Ōrakei Main Sewer and improvements at street level including new street furniture, lighting, tree planting and bus bays. Completed in October 2020.
- Contract Three (C3), delivered by Link Alliance: deliver the City Rail Link 3.45km twin tunnel underground rail line from Auckland’s Waitematā Station (Britomart) to a redeveloped Maungawhau; Design and construction of two new underground stations midtown, Te Waihorotiu Station and Karanga-a-Hape Station off Karangahape Road, and a long-term maintenance contract.
- Contract Six (C6), delivered by March Bessac Joint Venture: replacement of the stormwater line in Mt Eden. Completed in August 2019.
- Contract Eight (C8), delivered by KiwiRail and CRL Ltd: improvement works at Ōtāhuhu and at the Strand in Parnell. Completed October 2020.
- Contract Nine (C9), delivered by KiwiRail, Martinus Rail and CRL Ltd: additional connections, platform widening and track modification at the eastern end of Waitematā Station (Britomart). Construction complete on all sections apart from Stage 4 to 6 "Track" Contract for track slab and track works in the vicinity of Platforms 1 and 5. Expected construction completion expected January 2024.