The platforms at Flinders Street Station were heaving with stranded commuters on Wednesday night. Credit:Leonie Wood The viaduct is the railway bridge over Flinders Street near the Melbourne Aquarium, which connects Flinders Street and Southern Cross stations. Made up of six tracks of varying ages, the viaduct forms the main link between the eastern and western parts of Victoria's rail network. "We could not access the City Loop and we were forced to run services direct from Flinders Street," Metro said. "This affected 240 services and meant long delays for many of our customers. "When we have an issue in the centre of our network it can be very disruptive and that's what our customers experienced last night.

Thousands of commuters were stranded on overcrowded platforms on Wednesday night. Credit:Courtesy of @Andrew_Lund, via Twitter "We know it was a long and frustrating journey home for many people and we sincerely apologise for their experience. "While there is never a good time for a network fault, the middle of a peak is the worst possible timing." It threw the entire network into turmoil, with major delays across all but the Stony Point line. Thousands of commuters were left stranded on overcrowded platforms, and overcrowded trains. The signal fault was not fixed until 9pm. Trains leaving the CBD were still packed at 9.30pm.

Frustrated commuters vented their anger on social media, criticising Metro's handling of the meltdown, and calling for the train network's ageing signalling system to be upgraded. Signal failures are one of the biggest sources of delay on the Metro system. Some signals, called interlockings, are 100 years old, but have a design life of 35 years. "Much of the signalling equipment on the network is antiquated and presents significant impact potential on the network's performance," Metro told Fairfax Media last year. The age of the signals makes them increasingly prone to failure and expensive to maintain, due to "the diminishing number of technicians with the relevant maintenance experience" to fix them.

Public Transport Users Association spokesman Daniel Bowen said an upgrade of the signalling system was long overdue. "Once again we're reminded that when the train system has major problems, Melbourne comes to a halt," Mr Bowen said. He said both Metro and the state government needed to identify precisely what went wrong and what could be done to prevent it happening again. "If systems need replacing, or need to have more redundancy to protect against faults, or need to have better maintenance, then the government needs to make the investment to stop shut downs like this occurring again," he said. The overcrowded platforms at Flinders Street also had commuters calling for better safety measures, after the chaotic scene was compared with a clip in Metro's own 2012 Dumb Ways to Die ad campaign.

Premier Daniel Andrews apologised to commuters for the train meltdown. "It's a great disappointment and a great disruption for many people. I want to apologise to them," Mr Andrews said. "It's very regrettable what happened last night, I apologise to everybody impacted by it, but be in no doubt, we're going to give this world class city a world class public transport system, but that does take some time." Shadow public transport minister David Hodgett said preparations for such an event should have been better, as well as communication from Metro.

"There is no plan by the government, or no plan by Metro to try and get information quickly out to people [about] exactly what the problem is and the best way to navigate their way home," he told radio station 3AW. Rail, Tram and Bus Union spokesman Amedeo D'Aprano echoed Mr Bowen's sentiments. "Metro needs to be making sure that all the money they are given goes into maintaining the network to ensure service delivery and the safety of the travelling public, not their private shareholders," the spokesman said. "As Melbourne's monopoly train operator it's imperative they put the needs of travelling Victorians first and foremost ." - with Adam Carey