Auckland's City Rail Link tunnel boring machine breaks through after 7-month underground journey

A giant tunnel boring machine broke through into the Aotea Station in central Auckland today, marking the end of its seven-month underground journey for the City Rail Link project.

The machine, dubbed Dame Whina Cooper, cut through a concrete protective wall into Aotea, marking the end of a mammoth tunnelling endeavour that started at Mt Eden in May.

Transport Minister Michael Wood, Auckland mayor Phil Goff, Cooper's whānau and City Rail Link (CRL) workers were on site for the moment.

"Our aim was always to get into central Auckland before Christmas and here we are – pleased and proud at what a committed Link Alliance team of contractors has achieved in some pretty testing times," said CRL chief executive, Dr Sean Sweeney.

"It's been a hard year but a better rail network for an international city like Auckland is getting closer."

The breakthrough marks a seven-month underground mission. Photo / Brett Phibbs

The Crown and Auckland Council are CRL's sponsors, and Wood and Goff were impressed with the progress made by the project despite the pandemic.

"It's great to see Dame Whina Cooper finish its journey – a positive milestone that is an exciting Christmas delivery for Auckland," Wood said.

"CRL will form the heart of linked-up high-capacity rapid transit network for the city."

Goff described the Aotea breakthrough as remarkable.

"While we continue to face challenges due to the pandemic, we are making good progress on delivering this essential infrastructure," he said.

"Once complete, the CRL will be a gamechanger for the region, doubling train capacity, reducing journey times and carrying the equivalent of up to 16 extra traffic lanes into the city at peak times."

Sweeney described the breakthrough as the "icing on CRL's Christmas cake" after a year of "significant advances" - reopening the city's restored Chief Post Office, connecting Aotea to the Albert St section of tunnels, mining New Zealand's deepest station at Karangahape, relocating the huge Huia 2 watermain at Mt Eden and navigating a Covid-19 pandemic.

"This breakthrough is a great morale booster for a dedicated team working at times under stressful conditions. It gives us great confidence going into the second half of the project next year," he said.

"Covid is responsible for a lot of disruption. CRL Ltd and the Link Alliance are now assessing the impact of that disruption on construction timetables and costs. We'll have a clearer picture next year.

"What is important today is that the Link Alliance has progressed a vital piece of Auckland's transport infrastructure."

During its seven-month journey, the tunnel boring machine (TBM) multi-tasked – cutting into the earth, removing spoil to the surface, and installing the concrete panels that line the tunnels.

Following centuries-old mining tradition, the TBM's name recognises a woman of significance and mana – for CRL it is Dame Whina Cooper. Today's breakthrough occurred less than a fortnight after the Māori champion's day of birth in 1895.

Cooper's son, Joseph, said the breakthrough reflects in many ways the impact his mother made on Māori and all people living in New Zealand/Aotearoa.

"Kite matau nga iwi te kopura marama i tera moka o Te Kauhanga Raro – we the people can see the light at the end of the underground sacred passageway," he said.

The breakthrough marks the end of the first of two underground journeys for Dame Whina Cooper.

The front section, known as the shield, will be lifted out in sections and transported back to Mt Eden.

The shield's supporting sections, or gantries, will move back through the newly excavated tunnel to Mt Eden and reconnected with the shield for the TBM's second drive to Aotea next year.

A completed CRL connects a redeveloped Mt Eden station directly with Auckland's main station at Britomart.

Two underground stations along the 3.45km route – Aotea and Karangahape – will "make it easier to access the central city for work and pleasure", CRL says.