A new report showing the value rail delivers to New Zealand is being used to defend the Government's decision to invest more in it.
The report by the accountancy firm EY, commissioned by the Transport Agency, found the value of rail to the country is about $1.5 billion dollars a year.
Most of the value comes from the reduction in traffic congestion, mainly from passenger rail services in Auckland and Wellington.
Reduced climate emissions and fewer road accidents were other benefits of rail, the report said.
Its estimates were conservative, EY said.
Transport Minister Phil Twyford said the government wanted to take a smarter approach to investing in transport and the report would inform its decisions.
"It's a really helpful contribution to finding a better balance in our transport system rather than just pouring billions of dollars into a handful of urban motorway projects."
Mr Twyford accused the previous government of sitting on the report, which was commissioned in 2016 but not released by the National-led government.
The Labour-led government has said it will invest in regional rail through the $1bn a year regional development fund it agreed to set up as part of Labour's coalition agreement with New Zealand First.
That includes the establishment of a light rail network in Auckland.