Positive moves for Auckland City Rail Link 14 Apr 2016

Auckland City Rail Link (CRL) takes a significant step forward with selection of two consortia to commence first phase construction in the Downtown area, including preparations for cut and cover tunnel construction at Mount Eden Station.

Fig 1. Cut and cover and TBM alignment of CRL

Project director Chris Meale said there had been wide interest from the New Zealand construction industry, and that Auckland Transport has appointed two Joint Venture contractors for the initial works: the Downer NZ and Soletanche Bachy JV; and Connectus (McConnell Dowell and Hawkins JV) for the first phase of design at a cost of about NZ$3 million. The next phase will provide for a negotiated contract to construct the 3,400m of a total 3,600m of twin running tunnels of the City Rail Link, 2,200m of which will be excavated using a TBM of approximately 7m in diameter.

The Downer-led joint venture is chosen to progress the CRL works through and under Britomart Station and Queen Street to the Downtown Shopping Centre site with construction likely to start in early 2016 (Fig 1).

The contract includes establishing temporary accommodation for Britomart Station’s ticketing and customer service operations, underpinning the historic former Chief Post Office building to allow the construction of the 1,000m-long cut and cover rail tunnels beneath, and reinstating Britomart Station and upgrading urban space and surrounding roads.

“We are excited to have won a contract for what will be the most significant improvement to Auckland’s transport network since the opening of the Auckland Harbour Bridge,” said Chris Moloney of Downer.

CRL underground station vision

"McConnell Dowell and Hawkins have a combined history of over 100 years in infrastructure construction in New Zealand. It's enormously satisfying to be working together on a transport project that is helping to shape the future," said Roger McRae, Managing Director, McConnell Dowell.

"Auckland’s population is set to grow rapidly over the next 20 years, reaching close to two million with nearly four out of every ten New Zealanders calling the city home.”

Auckland Transport’s Chris Meale said: “We are now definitely on the way to building a key missing link in our city’s public transport network. Once completed, the CRL will turn a one way cul-de-sac rail system at Britomart, into a two way through system that will be able to carry 30,000 people an hour, providing an efficient and reliable transport choice for Aucklanders.”

The alignment of the tunnels generally follows the roads to minimise the amount of private property affected by the project. Due to the gradient of the landscape between Britomart and the western line at Mt Eden, and the limiting climbing capacity of the electric trains, the twin tunnels will vary in depth.

The main construction area will be at the southern end of the project adjacent to New North Road. The tunnel will be bored from this end to Mayoral Drive, and then the TBM dismantled and returned to the start for the second tunnel bore. Spoil from the tunnels will be removed from the Eden Terrace end.

The project schedule anticipates a tender being released for major TBM excavation later this year, with contract award in 2017.