Excavations done for $98m Manukau rail link

The digging is finished so the platforms are next to be built. Photo / Paul Estcourt

Auckland's newest railway trench has been excavated and is being fitted out in a $98 million project to link central Manukau with the main trunk line at Wiri.

About 47,000 cubic metres of earth have been dug and trucked to a nearby quarry since the project began in September, creating a 300m trench through Hayman Park between Lambie Drive and Davies Ave.

The trench, which is up to 7m deep and a smaller version of an 800m cut through New Lynn, is at the end of a future 2km rail link from Wiri.

When it opens in the second half of next year, it will house a station with two 160m platforms to be linked by stairs, escalators and a lift to a bus interchange in Davies Ave.

Like the $160 million New Lynn trench, the Manukau version has been built from the ground down, meaning pile walls and concrete spans between them were constructed before the earth was dug from underneath.

The completion of the excavation phase means the construction of a concrete base slab on which the platforms will be built is on track to finish next month, as is a stormwater pumping station.

A decision by Manukau City Council in 2008 not to support extending the trench east of Davies Ave at an estimated extra cost of $10 million was criticised by the Forum for Auckland Sustainable Transport as short-sighted, as trains will stop well short of the Southmall shopping centre.

But the station will be literally on the doorstep of a new campus which Manukau Institute of Technology plans to open above it in Hayman Park in 2012 with 1500 students, in the hope of increasing its roll to 25,000 by 2040.

KiwiRail is contributing $50 million to the project, which has been boosted by $33 million from Manukau City, Government and regional subsidies, and $15.2 million from the Auckland Regional Transport Authority.

The station's platforms will be able to accommodate six-car trains, as they will be almost three times as long as a single structure due to open in September at the end of the Onehunga branch line.

Auckland Regional Council chairman Mike Lee last week lashed out at the transport authority, a council subsidiary, for building a platform not even long enough for standard three-car electric trains due in service from mid-2012.

The authority said it was supported by KiwiRail in predicting that two-car trains would be enough to cope with patronage growth until 2016.

On the other hand, KiwiRail expects the Manukau station - part of the first new extension of Auckland's rail network since the 1930s - to compete with Newmarket as the region's second busiest after Britomart.