KiwiRail has rolled out a 30-year vision for Auckland that includes plans for a new rail line between Avondale and Southdown.

The new section of track would be the biggest development on the city’s rail network since the Britomart railway station opened in 2003, along with the City Rail Link (CRL), and run on land designated for rail since 1955 alongside SH20 and through Ōnehunga.

The project is part of the Auckland Rail Programme Business case put together by KiwiRail in conjunction with Auckland Transport to future-proof passenger and freight rail for the growing city.

It is still in draft form, unfunded and unapproved, but has a preliminary price tag of $22 billion, including about $6b for the new rail line that would require huge earthworks and take years to build.

KiwiRail chief executive Peter Reidy said with Auckland expected to account for 40 per cent of New Zealand’s population growth over the next decade, “this is the plan we have put up... to move people and freight”.

KiwiRail chief executive Peter Reidy. Photo / Jason Oxenham

The plan contains three big items - removing level crossings, a fourth main line between Westfield and Wiri, and the Avondale to Southdown line.

KiwiRail head of capital projects Dave Gordon said building the Avondale-Southdown line meant any freight to and from the north would not go through the CBD, and open up a series of loops for passenger rail on the Auckland isthmus.

He said the new rail line would largely depend on moving the Port of Auckland, and a possible inland port in West Auckland.

The new line could be partially trenched/tunnelled through Ōnehunga, “but there’s no doubt it would be a disruptive thing”, Gordon said.

The plan is separate to the current work programme KiwiRail is undertaking in Auckland, including the $330 million upgrade of the rail lines, $375m electrification of rail from Papakura to Pukekohe, plus $495m for two new stations along the route; and the $318m third new line between Wiri and Quay Park.

These projects are being done to support the opening of the $5.5b City Rail Link in 2026.

The 3.4km twin-tunnel City Rail Link is due to open in 2026.

Work has already started on removing six pedestrian crossings and one road crossing before the CRL opens, but the remaining crossings will not all be removed until a decade or so afterwards.

AT chief executive Dean Kimpton said within the next 10 to 15 years, Auckland will have another 300,000 people, and by 2050, another 700,000 people.

“This programme is designed to enable those people to move so we don’t congest our roads, and the roads can be used for those who need to drive,” Kimpton said.

Reidy said the next step is for the draft business case to go to the KiwiRail and AT boards for sign-off and how to fund it, before detailed business case work.