KiwiRail will today begin geotechnical investigations along part of the route of the proposed rail link to Northport.
The work will begin at Mata Hill on the route of the 20-kilometre spur line mooted from Oakleigh east toward Marsden Point. It will involve boring to depths of 30 metres for rock sampling and analysis.
“We’ve held a designation for this rail spur for several years and are very pleased to be now taking steps to determine how the line would be built,” KiwiRail acting chief executive Todd Moyle said.
“These investigations will provide us with more detailed information about the design and potential construction methods for the link, as well as costs and timeframes.”
The study will inform a business case for Northland rail currently being developed by the Ministry of Transport. KiwiRail is also investigating the other associated works needed on the North Auckland Line to allow for more freight to be carried by rail in Northland. Bringing the line up to standard to handle major freight volumes may cost more than $2 billion.
In August, the government named a five-member working group to develop a strategy for better integrating transport logistics chains in the upper North Island.
It was specifically tasked with considering options to relocate Ports of Auckland to Northland, meeting a pre-election pledge of coalition partner New Zealand First. The group will also consider priorities for other transport infrastructure, covering road, rail and coastal shipping.
The government is trying to get ahead of the major growth all the country’s ports are facing as they compete to export increasing volumes of logs, meat, dairy products and fruit. Several are expanding their berthage to meet that demand while also coping with the growing cruise ship industry.
Northport, next to the Marsden Point oil refinery, handled 3.56 million tonnes of cargo in the June year- three-quarters of it logs. Ports of Auckland handled 6.8 million tonnes of bulk and break-bulk cargoes and almost 974,000 containers in the same period.
But whereas Auckland is increasingly constrained, Northport believes it can more than double its current deepwater berthage to almost 1.4 kilometres of wharf space and its port area by 56 percent to 75 hectares.
The cost of building the new spur line to Marsden Point was estimated at $100 million a decade ago. But the main cost of upgrading the line for heavy freight volumes occurs on the rest of the route. The line currently carries one weekday return freight service to Auckland, mostly dairy and forestry products.
The line from the South Auckland rail hub at Westfield to Whangarei has 13 tunnels and 132 bridges. KiwiRail previously estimated the cost of bringing those up to standard for containers would be about $50 million.
Getting the line from Waitakere, in west Auckland, to the standard of the Hamilton to Tauranga link would be about $500 million, KiwRail asset manager Dave Gordon said in a presentation in Northland in 2016.
But were Northport to become a major export operation, KiwiRail would need to be able to move heavy freight volumes from south of Auckland through the city’s increasingly busy rail network.
That would probably require triple-tracking of the line from Newmarket or Avondale at a cost of another $2 billion to $3 billion, Gordon said.