Patronage on Route 3, which runs through Caulfield, Balaclava and St Kilda before reaching the city and Melbourne University in Carlton, soared by 180 per cent in the 10 years to 2016/17, rising to 11 million annual boardings. On Route 5, linking Malvern East and the university, via Armadale, Windsor and South Melbourne, it grew by 120 per cent. Route 78, a short line connecting St Kilda, South Yarra and Richmond, saw an 80 per cent increase over the decade. Melbourne’s busiest tram routes are the 96 (53,000 patrons every week day), the 109 (49,000) and the 86 (41,900), shows PTV data for financial year 2016/17, obtained by the Victorian Greens. The route-based patronage figures — which the transport bureaucracy keeps hidden from the public — also reveals that on many lines, passenger numbers on weekends and public holidays now rival tram use during a typical week day.

On an average Saturday, more people use the 86, 96 and 109 trams than nearly three quarters of the network’s tram routes during the week. On Sundays, almost 32,000 people ride the 96 tram, slightly less than the 33,500 people using the Route 75 tram (the city's fourth-busiest) on an average week day. Two months out from the state election, Greens transport spokesman Sam Hibbins has called on the government to commit to ordering more low-floor accessible trams to deal with the growth. "There is too much focus on extending the life of older trams rather than investing in new ones," he said. "There are piecemeal upgrades going on, but no holistic long-term plan to upgrade the system."

A business case looking into the design, roll-out and number of “next generation” trams was under way, a government spokeswoman said. Thirty E-Class trams have been ordered since 2015, the state government says. Credit:Penny Stephens "We’re making a record investment in delivering the public transport system to get Victorians where they [are needed], safer and sooner," she said. Thirty E-Class trams have been ordered since 2015, taking the total fleet to 80 trams, she said. But the Rail, Tram and Bus Union claims that on average, about 65 trams are out of service due to maintenance - a number the union warned would likely swell as the weather heats up, putting scheduled services at risk.

“We have drivers ready to do the job, but they’re sometimes sitting in the depot because of a faulty tram that can’t be be run and there’s no tram to replace it," RTBU's Tram and Bus Division secretary Phil Altieri said. Public Transport Users Association spokesman Daniel Bowen said more trams were needed, but he emphasised that the number of services must be ramped up, calling for trams to run every 10 minutes at least, at any given time. The extra services should be initially rolled out in the evenings and on weekends, he said. “Some trams are crowded even at 10 at night - and there are long waits of 20-30 minutes between services in the evenings," Mr Bowen said.