In the second of a two-part explainer on New Zealand's largest infrastructure project, property editor Anne Gibson tells why the $4.4 billion City Rail Link project's tunnel boring machine will get a female name, how and where she will work, her route and what's at stake.
"Tunnel boring machines have to have names," explains CRL chief executive Sean Sweeney from his L17 boardroom in the AMP tower on Lower Albert St.
"It's traditional because tunnellers are superstitious. The names the machines are given are always female."
He's talking about the machine which will in the next year begin digging the C3 or most expensive part of Auckland's City Rail Link project, where costs increased in April from $3.4b to $4.4b due to original estimates dating back to 2014, high construction sector inflation and the project's scope and size expanding to accommodate larger-than-expected passenger numbers and usage.
While cut-and-cover trenching work has been going on for years from Britomart up Albert St, now is the next phase of the biggest transport project New Zealand has undertaken.
CRL is almost twice the length of the Lyttelton tunnel, a transformative piece of infrastructure to unlock the cul-de-sac Britomart and create the crucial link to unlock the entire rail network- not a loop but a link just like Waterview linked two motorways.
The tunnel boring machine about to arrive in Auckland soon for the massive C3 part of the project will drill twin-tunnels from Mt Eden to the existing tunnels on Albert St.
Will she perhaps get a Te Reo Māori name? Or a French name, as a nod to the many French personnel leading the Link Alliance which on April 17 was named preferred bidder? Those French come from Vinci, part of the alliance of firms - although the formal contract is yet to be signed. That could be a few weeks away still.
It's too early to speculate about the name but what is more certain is that the machine will most likely be built overseas, perhaps in China, and then imported by preferred bidder the Link Alliance, by sea.
It's likely that only then will a public consultation period follow where the name is chosen, as long as the Link Alliance in charge decides to do it that way.
Let's Talk - CGT 'totally appropriate, time for us to catch up'
Victims of the City Rail Link: Antidepressants, 110-hour work weeks
"There's a lot of tradition. Link will lead that," Sweeney says of the naming which is all to do with St Barbara, the patron saint of armourers, artillerymen, military engineers, miners and others who work with explosives.
She was born around the mid-third century and it's due to her, explains Sweeney, that tunnel boring machines get female names.
Hence, Waterview's impressive 14m diameter tunnel boring machine Alice, named after a public consultation, in reference to the children's storybook character who went down a hole.
There's more than just the name too. A physical statue of the patron saint precedes all work. That happened when effigies of St Barbara arrived on the Waterview twin-road tunnel project some years ago.
"The Waterview Tunnel got a permanent resident, St Barbara, the patron saint of tunnellers and all others who work underground," it was announced at the time when that project started.
"Tunnellers look to St Barbara for protection and in keeping with tradition, statues of her were placed in both tunnels. They overlooked crews as they headed underground to work and brought them back safely at the end of their shifts."
In Christian history, St Barbara fled into a cave to hide from her father after she had converted to Christianity against his wishes. Her hiding place was eventually discovered and she was killed.
Legend has it her father beheaded her, then he was struck by lightning and killed.
Whatever name the yet-to-be-seen CRL tunnel boring machine gets, a statue of St Barbara will be lowered down in advance of that big, sophisticated piece of equipment digging itself into the hole, Sweeney says.
More details were provided about the TBM's likely route: "Tunnel boring will start from Mt Eden, there will be one machine, once it gets to the hole mined for the Aotea station in the central CBD, it will be lifted out, put on a truck for the drive back to Mt Eden where it will start its second drive to Aotea for the other tunnel."
Sweeney says perhaps the biggest threat to the as-yet-unnamed TBE is volcanic lava rock around Mt Eden. He cites projects in Melbourne, where he lived for many years, striking basalt rock "which bends and destroys teeth in the piling rigs."
But Sweeney also dismissed this threat: "I've taken a view we have two world-class firms as part of the bid process," he said, referring to the two tenderers.
The winning Link Alliance announced on April 17 is Vinci Construction Grands Projets S.A.S, Downer NZ, Soletanche Bachy International NZ, WSP Opus (NZ), AECOM New Zealand Limited and Tonkin + Taylor.
The other short-listed but unsuccessful bid came from CPB Contractors Pty, UGL (NZ), Beca, Jacobs New Zealand and McMillen Jacobs.
In deciding on which bid to pick, Sweeney recalled: "We said we'd like them to show us reference sites."
CRL chiefs then visited Sydney's metro project with CPB Contractors and the extension of Hong Kong's rail network with French-headquartered Vinci.
"You were left in no doubt that these people knew how to build tunnels and stations all around the world. While they are big and complex and there are risks that go with big underground projects, these firms do this all the time," Sweeney said.
The new CRL tunnel boring machine has been usurped somewhat already. It was beaten by another much smaller version: just last month, CRL announced that a machine given the traditional French female name, Jeffie, had completed her underground journey.
"Mechanical muscle known as Jeffie has completed her underground journey below Mt Eden for CRL," the Auckland Council/Government joint venture said.
"Jeffie is a micro-sized tunnel boring machine used to build a new, 423-metre-long stormwater main 17 metres below city streets. The existing main between Water and Nikau Sts was in the path of the future CRL tunnels and had to be diverted," CRL announced.
Jeffie's journey brought the much better rail service one step closer to Aucklanders, Sweeney said.
"Jeffie began work in January with two jobs to do: excavating spoil and, at the same time, installing concrete segments for the new drain. She removed more than 2000 cubic metres of spoil, installed 208 concrete segments and made a sweeping curve underground to avoid a field of hard volcanic basalt rock in her way. During the journey, Jeffie encountered a part of Auckland's distant past - the remains of a tree thought to have been destroyed in a volcanic eruption some 20 thousand years ago," Sweeney said.
Jeffie was a popular name in France about 100 years ago and the machine is owned by the French firm, Bessac, part of the March Bessac joint venture, responsible for the main.
Jeffie is now being transferred to Ecuador in South America for a new job, and a new name.
CRL's scope is a redeveloped Mt Eden Station, where it connects with the north Auckland or western line and two new underground stations:
• mid-town at Wellesley and Victoria Sts provisionally named Aotea;
• Karangahape Rd, provisionally named Karangahape with entrances at Mercury Lane and Beresford Square.
Where will the tunnel tailings or soil go? Sweeney said that's up to the preferred bidder but Waterview's soil went to a quarry in the Wiri area and raised the floor of that giant pit by around 7m.
"That was a big part of the bid, working out where the dirt would go," Sweeney says. "One of the benefits of having Downer as the preferred consortia is they have been dealing with this all the way up Albert St. At the moment, we have a couple of unsolicited offers to take the spoil. We haven't put that on the table yet with the bidder."
• Part 1: The two big threats looming over $4.4b City Rail Link
City Rail Link in numbers
• $3.4b cost estimate forecast in 2014 before project started;
• $4.4b expected completed project cost announced in April;
• $1b increase from sector price rises, project scope extended;
• Twin-tunnels 3.45km long with two new stations - Aotea, Karangahape;
• Tunnels 7m diameter, compared to Waterview's 14m diameter;
• Tunnels will be up to 42m below ground surface;
• Ground-breaking: June, 2016 with ex-PM John Key.