Auckland’s City Rail Link project has completed installation of the second and final railway line below the central city.

The newly laid 3.4 kilometres of track will carry trains underground north from Maungawhau Station at Eden Terrace and connect with the two new central city ones – Karanga-a-Hape and Te Waihorotiu – and downtown’s Waitematā Station (Britomart). CRL’s southbound line was installed last year.

Dr Sean Sweeney, Chief Executive for City Rail Link Ltd said there is plenty to celebrate.

“Completing the two tracks brings us one big step closer to the next phase of the project – testing trains inside the tunnels mid-year, and from there handing CRL over next year to Auckland Transport and KiwiRail, who will operate and maintain it,” he said.

CRL Ltd’s main contractor, Link Alliance, and railway infrastructure company, Martinus New Zealand, installed the track on what is one of the steepest sections of railway in New Zealand. From Maungawhau the line drops 70 metres to Waitematā, which sits below sea level. At its deepest point, CRL runs 42 metres underneath Auckland’s busy Central Motorway Junction.

The final section of the northbound line was installed near Te Waihorotiu Station.

The project’s tunnel boring machine, named in honour of Māori rights activist Dame Whina Cooper, excavated most of the tunnels to clear the way for track laying. Other sections of tunnel, near Waitematā Station, were built by first digging trenches and then covering them over.

Link Alliance Project Director, Francois Dudouit, says conditions under Auckland were challenging with tight curves, a steep gradient and no room for heavy machinery to pass.

“We became New Zealand’s first construction organisation to gain a Rail Operators and Rail Access Provider licence under the Railways Act – an innovation that gave us the flexibility we needed to plan the job and get it done to the highest standard,” he said.

The focus for 2024 shifts to train testing and the fit out of the stations and tunnels, alongside landscaping and urban realm enhancements. The fit-out programme includes the installation of lifts, escalators, security systems, CCTV, electricity, signalling and communications.

All track laying across the project’s three sites is now complete. Altogether, New Zealand’s largest transport infrastructure project laid 11 kilometres of line. In addition to the underground lines, new tracks were laid at Maungawhau to connect CRL and the Western/North Auckland Line, and a short section of track was laid at the eastern end of Waitematā (Britomart) Station.

Over three years, CRL’s project-wide track laying programme used more than 1100 tonnes of steel, poured almost 11,000 tonnes of concrete, laid 4,000 sleepers and completed hundreds of rail welds, which smooth out the ‘clickety-clack’ joins where track sections meet, to give Aucklanders a smoother ride.