“A more congested rail network will lead to nationally significant productivity losses associated with longer travel times and worsening conditions for passengers, with some passengers potentially switching to road vehicles and causing additional road congestion,” the authority says in a report.
A failure to meet demand for rail travel would also make it harder for Victoria to reduce its emissions, the authority’s acting chief executive, Anna Chau, said.
“Recognising the growth that is going to happen, if the public transport isn’t in place, there is a risk that reliance on cars will lead to further environmental costs,” Ms Chau said.
The authority releases its latest Infrastructure Priority List for Australia on Thursday, identifying 121 projects and proposals of national significance.
Among the “nationally significant” initiatives it calls for are duplications to single-track sections of the Hurstbridge and Cranbourne rail lines in outer suburban Melbourne.
Duplicating the Hurstbridge line was critical because it connected with the neighbouring Mernda line, the report said.
The Mernda rail extension in Melbourne’s outer north opened less than six months ago, but already Infrastructure Australia is warning of future overcrowding and unreliability, owing to forecast passenger growth of 9.1 per cent a year.
The Mernda extension was built to service growth suburbs in the City of Whittlesea, one of Australia’s fastest growing municipalities. But the ability to run more trains each hour had been hamstrung by the Hurstbridge line and its single-track sections, Infrastructure Australia said.
It has similarly called for the eight-kilometre single-track Cranbourne railway line to be duplicated to ease overcrowding in Melbourne’s booming outer south-eastern growth corridor.
Labor promised at the state election to spend $750 million duplicating the line.
Ms Chau said both lines served booming parts of Melbourne.
“In this case, with that emerging time scale of five to 10 years, it is really important that we highlight these two corridors now as nationally significant problems so that governments can start planning for them,” Ms Chau said.
The Andrews government recently duplicated one section of the Hurstbridge line between Heidelberg and Rosanna, and promised before the election to duplicate another section between Montmorency and Diamond Creek.
But other parts of Melbourne, particularly in the northern suburbs, are at risk of growing far beyond the capacity of roads or rail lines to cope.
The authority reiterated its warning about the threat of runaway growth in Melbourne’s outer north, in an area it refers to as the “Hume corridor”.
The Hume Freeway and the Craigieburn railway line both risk being overwhelmed in the next decade, with the Craigieburn line on course to become Melbourne’s busiest by 2031. Demand is forecast to outstrip supply by a factor of four to one by 2031, while traffic volumes on the Hume Freeway are forecast to surge to 107,000 vehicles a day by 2031.
State Political Correspondent for The Age