Analysis: Premier gets squeezed, too

Melbourne's busiest railway lines will be overwhelmed by passenger growth within three or four years, leaving more and more commuters unable to board peak-hour trains, new figures show.

The city's rail capacity crisis is expected to hit hardest on lines in the western and northern suburbs, which are projected to hit bursting point at least seven years before the planned solution - the $11 billion Melbourne Metro rail tunnel - is completed.

The latest projections from Public Transport Victoria predict growth in peak-hour patronage of about 90 per cent on the Werribee/Williamstown lines between this year and 2025, 80 per cent on both the Sunbury and Upfield lines, more than 70 per cent on the South Morang line and more than 60 per cent on the Craigieburn line.

Some of these lines already experience peak-hour load breaches that prevent passengers boarding trains.

The capacity crisis is forecast to affect Melbourne's north-western suburbs worst because of an inability to run trains through the City Loop more frequently.

Three fast-growing lines - Craigieburn, Sunbury and Upfield - converge into one tunnel in the City Loop. The tunnel's signalling technology cannot handle more than 22 trains an hour.

The crowding problems on those lines is already infecting services on other lines, because Metro has been forced to move some peak-hour Craigieburn line trains out of the Loop and onto tracks normally reserved for Werribee and Williamstown services.

Metro has warned the government that Melbourne faces several years when rail services will fail to meet demand, resulting in crowded trains, deteriorating reliability and commuters being left stranded on platforms.

The problem will not be fixed until 2026 at the earliest, when the Melbourne Metro tunnel is scheduled to open. The tunnel will connect the Sunbury and Pakenham/Cranbourne lines, creating desperately needed breathing space in the City Loop.

The project remains largely unfunded though, with the Andrews government still counting on securing one-third of the $11 billion cost from Canberra and one-third from private investors.

Public Transport Victoria's 10-year projections paint a radically different picture in the city's east, where growth is mostly modest and under control.

The chronically overloaded Pakenham/Cranbourne corridor is projected to experience a further 60 per cent increase in demand, but will also benefit from a multibillion-dollar upgrade.

Sandringham line patronage is expected to grow by 40 per cent, the Frankston line by 30 per cent, the Lilydale, Belgrave and Hurstbridge lines by more than 20 per cent each, and the Glen Waverley line by as little as 5 per cent.

The growth projections were revealed in a recent presentation by PTV's general manager of service planning Huw Millichip to the Industry Capability Network, a business resource group, but have not been made widely public.

The projections pose a serious challenge for the Andrews government, which is banking on Melbourne Metro as the answer to the city's public transport growing pains, but has fewer plans to meet short-term demand.

Transport expert Chris Hale said the problem could be tackled by moving quickly to replace Melbourne's outmoded signalling system with newer technology that allows trains to run more frequently.

"The only way to address the capacity gap would be to get really serious about bringing in new signalling right now," Dr Hale said.

He said the former Napthine government had wasted valuable years pursuing a doomed plan to reroute the Melbourne Metro tunnel through Fishermans Bend. But he questioned why Labor was spending $360 million on a conventional signalling upgrade for the Cranbourne and Pakenham lines, when a completely new system was needed.

Public Transport Victoria spokesman Adrian Darwent said the government was progressively addressing rail network constraints and preparing a trial of high-capacity signalling on the Sandringham line.