Transport experts say it will be 2025 before trams can return to Auckland - four years later than a promise by Prime Minister Jacinda Ardern to build a tram line from the CBD to Mt Roskill.
Ardern promised trams to Mt Roskill by 2021 and to the airport and West Auckland within 10 years in her first public appearance as Leader of the Opposition at last year's elections.
"Only light rail [trams] is a game-changer for Auckland. That's why Labour is backing it," Ardern said days later in an opinion piece in the Herald.
To blindly push ahead with a multibillion-dollar tram connection to Auckland Airport would be a grave mistake.
Papers released to the Herald under the Official Information Act show Auckland Transport and external professional advisers say the "best case" timescale to start running trams to Mt Roskill is 2025.
Bringing forward the "best case" date would result in "significant additional risk", the experts said.
Last night, Transport Minister Phil Twyford would not commit the Government to the Prime Minister's timeline of light rail to Mt Roskill by 2021, saying only he was confident work can be completed sooner than the papers suggest.
"We are ambitious about fixing traffic gridlock in Auckland and building light rail [trams] in our biggest city is a complex task.
"There is a lot of work being done on this. I will have more to say about this soon," said Twyford.
Last week, Twyford told the Herald he hoped to have the project consented, financed and contracted, with work under way within the next two years.
Trams first operated in Auckland in 1902 and were removed from the city streets in 1956 along with 72km of tracks. In the 1950s, trams carried 100 million passengers a year when the city's population was less than 400,000 people.
The papers are made up of briefing documents to Auckland Mayor Phil Goff, who is a big fan of trams but has not publicly committed any money.
Last week, the Government put aside $4 billion for trams in Auckland in its draft 10-year transport plan.
A briefing paper to Goff last November contained "broad estimates" of
$2.17b to $2.985b for trams from the CBD to the airport. No costs were given for trams from the CBD to West Auckland.
The Labour-led Government, Auckland Transport and New Zealand Transport Agency are committed to building trams to the airport. Transport Minister and Te Atatu MP Phil Twyford has promised an immediate start on trams from the CBD to Westgate in West Auckland.
Some transport advocates believe trains or buses are a better solution for rapid transit to the airport. Writing in yesterday's Herald, physician Ross Boswell said a dedicated airport busway from Puhinui train station to the airport would be $2b cheaper than trams, carry twice as many passengers and take about the same time.
"Trams will run on a kerb-protected central reservation, limiting road traffic in each direction to a single lane shared between cycles, cars, buses and trucks, and restricting right turns into or out of Dominion Rd," said Boswell, who regularly uses public transport.
Australian Prime Minister Malcolm Turnbull yesterday pledged $5b towards a $10b project to run trains from downtown Melbourne to Tullamarine Airport. The Victorian Government is expected to fund the other half.
Auckland councillor Mike Lee said Melbourne has the most extensive and most sophisticated tram system in the world and to choose to go with trains is based on experience operating trams and trains, confirming international best practice.
"The Australian decision is instructive and should give our new Government (reason to) pause. To blindly push ahead with a multibillion-dollar tram connection to Auckland airport would be a grave mistake," said Lee, a big player in the renaissance of rail in Auckland.
In Sydney, a 12km inner city tram project has be called a "horror story", the cost has soared from $1.6b to a new estimate of $3.3b, Spanish contractors are demanding more money and businesses have been starved of customers and gone bust.
Last night, Goff said the advice he received in November has been superseded by work on a joint council-Government transport programme, but acknowledged there are challenges to speeding up work on light rail.
Goff reiterated his stance of refusing to commit any ratepayer money to light rail and said work to date on a proposed regional fuel tax of 11.5 cents a litre "does not include funding for light rail".
"I am in discussion with government around their funding light rail as a nationally significant programme," said Goff, noting its intention to fund $4b over 10 years.
New features about light rail to the airport
An underpass at Karangahape Rd is part of the plan for trams from Wynyard Quarter to the airport, according to official papers.
The underpass, at the intersection with Queen St, is necessary to manage the gradient and to provide for a stop in the area. Queen St will be closed to traffic north of Mayoral Drive.
Another feature of the $2.2b to $3b tram project is a new bridge in Upper Queen St to run the tram line over the central motorway to connect to Ian McKinnon Drive.
The Dominion Rd flyover will be removed for trams and plans are in place for a depot at Stoddard Place in Mt Roskill for testing, maintenance and repairs of the trams, costing $10 million each.
A law change is also necessary to allow a separate, dedicated corridor within the road for trams, which are defined as "rail vehicles" under the Land Transport Act.