Underground rail to Mt Eden requires trenches and shafts in several sites in central city

Big traffic and public transport challenges face downtown Auckland from construction starting in less than a year for the $2.5 billion underground railway to Mt Eden.

Auckland Transport disclosed yesterday that it hopes to start digging trenches across lower Queen St in January, meaning rerouting buses such as the Northern Express fleet.

That is expected to require the relocation of 16 bus stops.

The council body also expects to close the main entrance to Britomart Station, through the old Central Post Office, for about three years from March.

Temporary

ticketing machines and gates will be installed at the eastern end of the station to cope with peak crowds of about 4000 passengers an hour.

Albert St, one of the main bus feeder routes into downtown Auckland, faces some disruption from October as a stormwater main is moved to make way for a pair of “cut and cover” rail tunnels to be dug from Britomart as far as Wyndham St in a package of early works likely to cost about $250 million.

Although new pipes will be “jacked” under the ground, shafts will have to be sunk at three intersections.

Auckland Transport expects to start altering bus stops on several streets from midOctober, although tunnelling through Albert St will not start until about March.

The cost of the project’s first stage will be borne entirely by Auckland Council and its ratepayers through loans, until the Government comes on board from 2020 to share the main part of the project, including bored tunnels and two underground stations.

Two joint ventures were named yesterday as winning $3 million of final design contracts, with an expectation they will move seamlessly into construction after negotiations with Auckland Transport.

A consortium led by Downer NZ and assisted by French piling specialists Soletanche Bachy has been allocated the challenging job of bringing the tunnels out from under Britomart while underpinning the foundations of the former CPO and protecting it as a heritage building.

Those contractors will also dig across lower Queen St to the Downtown Shopping Centre, which Precinct Properties expects to start demolishing in the first half of next year to make way for a 36-level office and shopping tower costing $550 million.

Precinct will provide for rail tunnels under that site, where it will have to serve notice on about 80 retailers, while a second consortium of McConnell Dowell and Hawkins digs trenches from the other side of its centre to Wyndham St.

Auckland Transport said the Downer-led consortium’s responsibilities would include fitting out the eastern end of Britomart and reinstating the station and its surrounds once the digging was done.

A spokeswoman said that underpinning the CPO would be “very complex”.