Auckland Mayor Len Brown has promised some radical ideas to get the city moving again but the Government isn't convinced. Transport reporter Mathew Dearnaley examines the three big schemes on offer - and whether we're likely to see them happen.
Auckland will be pushing it to get a central railway loop by the centenary of when the idea was first dreamed up - in 1923.
Although a $2.4 billion tunnel is top of Mayor Len Brown's list of three congestion-busting rail projects, it suffered a serious blow this week when the Government accepted advice that it did not yet represent an economically efficient investment.
But Transport Minister Steven Joyce promised not to stand in Auckland's way if it was prepared to pay for gaining a land designation and buying properties with foundations along the 3.5-km route from Britomart to Mt Eden.
That has left Mr Brown determined to press ahead, even though property costs have yet to be assessed, in the hope of changing the Government's mind as ever more Aucklanders use public transport.
He claims a strong mandate for his election pledge to use rail projects to unlock Auckland's economic potential and turn it into "the world's most liveable city" as its population swells to more than two million by 2041 - 40 per cent of all New Zealanders.
Auckland Transport says the tunnel will form a two-way loop with the western and southern railway lines, more than doubling capacity by opening the dead-end Britomart station to through traffic.
It says Britomart will otherwise reach capacity soon after electric trains start running at a 10-minute frequency in 2014, making city streets even more clogged with traffic.
The organisation, which inherited a glowing business case commissioned by KiwiRail and the former Auckland Regional Transport Authority but rubbished by a Government review, hopes to build three new underground stations along the tunnel.
Chief executive David Warburton says that will expand the city centre to Newton and Mt Eden, and create a vibrant hub with a train stop within a 500m walk of most shops and offices.
He expects it to cut 10 minutes off the 30-minute travelling time from New Lynn to Britomart, and to ease train movements throughout Auckland's network.
The idea is hardly new. Railways Minister Gordon Coates came out in 1923 in support of a tunnel from the city to Morningside in an upgrade which included construction of the eastern line through Glen Innes.
It re-emerged several times but was killed off in the 1950s in favour of motorways and again in 1976.
The Government review found the $5 million business case far too optimistic in predicting "transformational" benefits of three and a half times the tunnel's cost, and instead calculated a return of just 40c for each dollar invested.
But even Mr Joyce has acknowledged its potential benefit in providing greater transport resilience and the Transport Agency believes the project could gain a high ranking if more evidence can be provided on land use integration and patronage forecasts.
It is the likeliest of Mr Brown's rail proposals to proceed but even if he could persuade the Government to write a cheque on Monday it would take at least until 2019 to build.
Second harbour crossing
Train tracks under Waitemata Harbour to Albany are the most ambitious of Len Brown's three big rail proposals - and the least likely to proceed.
Although the Transport Agency is considering whether to build harbour tunnels or a new bridge within 20 years, its latest study envisaged these as only for motorway traffic. It indicated separate rail tunnels would cost considerably less at $1.6 billion than a $5.3 billion pair of motorway tubes, but said they would be difficult to justify for 30 years while the Northern Busway still had capacity to meet demand.
That was in contrast to an election pledge of Mr Brown for trains to Albany within 15 years, after the central city rail tunnel and links to the airport.
In announcing his determination this week to start route investigations for the city tunnel, despite no Government money, he said it would "open up the rail option to North Shore with a second harbour crossing imminent".
A northern link has won strong backing in recent opinion polls, including from 71.3 per cent of more than 6000 Auckland members of the Automobile Association.
But support for the other two rail projects was even stronger, and only 21.4 per cent saw the northern link as the most important.
The AA noted that just 15.2 per cent of survey participants indicated they would use trains if deprived of their cars, and said support for the projects may change once they knew how much these would cost and who would pay.
Transport Minister Steven Joyce has said the $1.6 billion harbour rail tunnels estimate is just the start and the full northern project may cost up to $10 billion. He acknowledged that it was just a "rough costing" in the absence of a proper study by KiwiRail. But he said officials had told him running rail to the North Shore would probably require extra tunnelling through main population centres as the busway corridor would be unsuitable for trains.
They had also warned of "huge additional investment" south of the harbour for new underground stations to cater for trains arriving from the North Shore.
Rail tunnels across the harbour were integral to a study in 2008 for the former Transit NZ and Auckland councils, in which an underground station was proposed for Gaunt St in the Tank Farm redevelopment.
There have also been suggestions that trains from the North Shore join the rail network through a new underground station proposed for Aotea Square as part of the city tunnel project. The Campaign for Better Transport meanwhile warns spiralling oil prices could put pressure on the Northern Busway far earlier than the Transport Agency thinks.
Airport trains appear the most popular of Auckland Mayor Len Brown's three rail proposals, although their numbers would be limited without a central city tunnel.
Mr Brown has promised an airport rail service within 10 years, once the tunnel provides more network capacity by opening Britomart to through traffic.
But airport rail was the most popular project among 300 people surveyed by the Herald before last year's mayoral election - with 53 per cent saying they would be willing to pay higher rates to make it happen.
It won support in recent weeks from 82.5 per cent of more than 6000 surveyed Auckland members of the Automobile Association, and was ranked by 43.3 per cent as the most important of the three rail proposals.
The most recent cost estimate, from a 2008 study for the former Auckland Regional Transport Authority, was $1.45 billion for a loop running via Onehunga and Puhinui on the main trunk line.
That will be revised in a new study into "airport transport solutions" for organisations including the Transport Agency, Auckland Transport, KiwiRail and the airport company.
Auckland Transport expects an initial report within weeks, containing a short-list of options with high-level business cases for each, before a preference emerges by Christmas.
It hopes by then to be looking at how potential routes can be protected by land designations.
But the Campaign for Better Transport, which raised a petition in 2008 of more than 10,000 Aucklanders in support of airport rail, believes the new study is too broad in investigating buses as well as trains as candidates for a rapid transit corridor.
Convenor Cam Pitches says that is turning back the clock from the earlier study, which nominated heavy rail as the best option.
It was his organisation which persuaded the former Transit NZ to make the piers of the new duplicate motorway bridge over the Manukau Harbour strong enough for trains, and for a rail corridor to be provided as far as Walmsley Rd in Mangere.
Auckland Council transport committee chairman Mike Lee says it should be a straightforward matter to extend the Onehunga railway line - on which daily patronage has grown to 1200 passengers since it reopened in September - to Mangere and then the airport.
He believes Britomart could cope with an extension of Onehunga's half-hourly service to start with, although the city tunnel would be needed for higher-frequency airport trains.