Some people have the view that building Auckland’s City Rail Link is a bit like playing with a giant Lego or Meccano set – it’s as easy as clicking plastic tiles together or joining up a metal sections with nuts and bolts - albeit lots of them!
I wish it were child’s play, but nothing could be further from the reality of the challenges my team faces daily. In fact, I describe our next big construction step as a massive voyage into uncertainty and engineering complexity.
A piling rig has started the hefty job of drilling holes deep into Mt Eden soil for the first of 66 concrete piles that will support a curving wall for the southern portal or entranceway to the two tunnels that will run all the way to Britomart Station in lower Queen Street.
Mt Eden will be our “base camp” for the biggest contract of CRL work to complete the tunnels and stations, and I’m not exaggerating when I say it marks the launching pad for the voyage into engineering uncertainty.
Nothing on this scale has been undertaken before, certainly not in Auckland and probably not in New Zealand, since the massive hydro-electric projects last century.
I doubt any of those projects would have been undertaken with the central city engineering complexity, disruption and scrutiny or the legislative legacies – safety regulations for working underground in the wake of Pike River is one example – that oversee our work.
Building the portal retaining wall is one visible sign of the complexities challenging my team.
Before we could start piling, some 30 buildings had to first be demolished – one 19th century colonial cottage was saved – to clear the Mt Eden site.
In 10 months, a completed site will then become our launching pad – not aimed vertically at the heavens but at a more modest horizontal destination, central Auckland.
The TBM machine is arriving from China in sections next spring to be reassembled in front of the portal. Early next year, it will start worming its way 1.6 kilometres under Auckland to the Aotea station and connect with the cut-and-cover tunnels we already have under construction from Britomart and along Albert Street.
This is where our uncertainties and complexities really come into play. We’ve planned our programmes of work as best we can, but I know from experience that you can’t nail everything down.
Thousands of bore holes have been punched into the ground along the project’s route to map soil conditions, but there still may be gaps that impact on our tunnelling – last year we unexpectedly came across buried fragments of a tree that could be as old as 40,000 years.
Building two underground stations each 400 metres long is an unknown engineering challenge, as is navigating our TBM through Auckland’s volcanic foundations and dragging it across the huge holes dug for the stations – not once, but twice.
And at the end of all that, perhaps the most complex of all – safely integrating 3.45 kilometres of new railway with the rest of the network.
It is no idle boast when I say that one of CRL’s legacies will be the upskilling of a workforce that will benefit New Zealand long after we’ve finished. This workforce will be well placed to underpin the ongoing delivery of vital NZ infrastructure over the foreseeable future.
CRL’s largest programme of work is being delivered by the Link Alliance, a team that includes the best expertise from New Zealand and overseas.
I have no doubt that the months ahead for the Link Alliance and City Rail Link Ltd will be uncertain and they will be complex – certainly not child’s play BUT this is our challenge to manage as we deliver a world class rail system necessary for Auckland’s future growth.