Auckland Transport has awarded advanced design contracts for the first stages of the $2.5 billion underground rail line from Britomart to Mt Eden, to start construction within a year.
Contracts worth $3 million have gone to two joint ventures which will also be the preferred contenders for the first construction stages from Britomart to Wyndham St, via Customs and Albert streets, expected to cost about $250m.
Those will involve digging a pair of "cut-and-cover" tunnels from early next year from the former Chief Post Office at Britomart for the first part of the 3.5km rail route, the rest of which will involve deep underground bores.
A consortium led by Downer NZ, assisted by French piling specialists Soletanche Bachy, has been appointed for the challenging job of taking the tunnels out from under Britomart while preserving the former CPO as a heritage building.
It will take the tunnels across Lower Queen St to the Downtown Shopping Centre, which Precinct Properties is expected to start demolishing in March to make way for a new high-rise development.
Precinct will provide for rail tunnels under that site, while a second consortium of McConnell Dowell and Hawkins digs trenches from there to Wyndham St.
Preparatory work is expected to start as early as October in Albert St, clearing the way for the tunnels by relocating a major stormwater line.
Although the construction contracts have yet to be finalised, Auckland Transport says the Downer-led consortium will be responsible for establishing temporary accommodation at the eastern end of Britomart Station for ticketing and customer-service operations, while the main entrance through the CPO building off Lower Queen St was closed so its foundations can be "underpinned" for the tunnels to weave through them.
Auckland Transport project manager Chris Meale said today that his organisation was "now definitely on the way to building a key missing link in our city's public transport network".
"Once completed, the CRL [City Rail Link] 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 an hour, providing an efficient and reliable transport choice for Aucklanders."
Auckland Council has arranged funding for the first stage to Wyndham St while waiting for the Government to share costs -- but not before 2020 -- for the main part of the project.