THE earth is moving in anticipation of Manukau's $50 million rail link.
Diggers have started excavating the 300-metre long trench where trains will draw up beside two platforms at the new railway station at Davies Ave.
KiwiRail project manager Paul Crawford says the start of digging is an important milestone along the track to the Manukau rail station opening by early next year.
"It's going very well," he says.
The rail trench will be seven metres deep and up to 18 metres wide.
The trench, two 180-metre platforms, the station, its surrounds and services should all be finished by September.
Work will then start on laying 1.8km of tracks between Davies Ave and the southern line at Puhinui.
Mr Crawford says it's exciting to see the station start to take shape after six months of building the trench walls underground.
They're formed of 740 alternating reinforced and unreinforced concrete piles bored up to 13 metres deep. They overlap to form watertight walls the length of the rail trench.
Tension piles have also been driven deep into the sandstone to anchor the 270-metre base slab.
They're needed because the trench is being excavated below water level, Mr Crawford says.
"Groundwater is at about four metres and because the slab will be two or three metres below that it needs to be held down so it doesn't float away."
Before the base slab can be poured, contractors will spend three months excavating 47,000 cubic metres of silty sand between the pile walls. The big dig has just started at the far end of the trench under the Lambie Drive bridge.
Leighton Works project manager Marty Craill says they're "ramping up" the number of subcontractors on the site to about 40 now excavation has started.
"We're using long reach excavators to reach over the capping beams."
The diggers will also have to negotiate the concrete props which span the trench every 13 metres to stop the walls collapsing inwards.
Mr Craill says they'll be digging until mid-June and then spend a couple of months pouring the 2300 cubic metres of concrete for the base slab.
When it's finished, there'll be double-tracked rails with platforms on each side overhung with canopies to protect passengers from the weather.
Arriving passengers will step on to platforms around six metres below ground level and take escalators up to a covered eight-bay bus interchange on Davies Ave.
The Manukau rail link and station is a collaboration between KiwiRail, the Auckland Regional Transport Authority and the Manukau City Council.
Around 600,000 rail passengers each year are expected to use the station, making it one of the country's busiest. About 1.2 million people are expected to use the bus station each year.
The station will also be part of a Manukau Institute of Technology tertiary campus which is due to open its first stage to students at the start of the 2012 academic year.
- © Fairfax NZ News
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