The first stage of the Victorian government's suburban rail loop will cost up to $34.5 billion to construct, according to the project's business case.
The business and investment case, released on Thursday, focuses on the first two sections of the 90-kilometre orbital rail line - the eastern stretch from Cheltenham to Box Hill and the northern part, from Box Hill to Melbourne Airport.
Early works of the east section will cost between $30 to $34.5 billion across 14 years, with construction expected to begin in 2022 and finish in 2035.
The northern section will be built by 2056.
The government said the loop will support 24,000 jobs across Victoria, and connect people to around 550,000 jobs in the precincts around the stations.
They forecast it will take 600,000 car trips off the roads every day, slash public transport travel times by an average of 40 minutes for a one-way trip and stimulate $58.7 billion in economic, social and environmental benefits to the state.
The government plans to fund the project with support from the Commonwealth government and an "a mix of value capture opportunities".
"Victorians voted for Suburban Rail Loop and we're going to get on with it - it'll change the way our city travels, ensuring every Victorian has access to housing, education and jobs as our state continues to grow," Transport Infrastructure Minister Jacinta Allan said in a statement.
Billed as Australia's largest transport project, the suburban rail loop was announced just months before the 2018 election, with no detail attached.
