Labor transport spokeswoman Jo Haylen said the Liberal government was warned a year ago that components in the digital train radio system were already obsolete. “They knew that this could put the whole train network at risk but not enough has been done because there is no accountability. Passengers are yet again paying the price because no one knows who is in charge,” she said.

Sydney Trains said it continually reviewed the lifecycle management of systems and,in 2021,identified that parts of the digital train radio system would become obsolete over the next five years.

“The technology that supports the DTRS is very stable and used widely in railway systems around Australia and the world and upgrades are a normal part of the ongoing maintenance program,” the spokesperson said.

“Transport for NSW and Sydney Trains are working together on a plan for the broader technology upgrade for train radio systems,while continuing to keep the current system operating reliably.”

Asked if train drivers would receive hand-held radio devices,Sydney Trains said it was not uncommon for analogue radio to be used as an additional backup.

Transport experts and unions have warned that last week’s meltdownunderscores an under-investment in Sydney’s double-decker train network,especially on rail maintenance.

Mathew Hounsell,a researcher at the University of Technology’s transport research centre,said the next government needed to invest in Sydney’s heavy rail network and “not just flashy new metros” rail lines. “A program of continuous capital investment is required to keep the city’s most important trains running,” he said.

The Electrical Trades Union,whose members include rail workers,said Sydney commuters’ confidence in the reliability of the train network was hanging by a thread due to chronic underinvestment in maintenance.

“This is an absolute shambles. But it’s a logical consequence of treating the train network as an irritating line item on a budget paper,rather than a critical public utility,” the union’s state secretary Allen Hicks said. “It’s time to end the cycle of cuts and outsourcing and rebuild the internal capacity of Sydney Trains.”

However,the rail operator said it delivered an extensive program of maintenance across the rail network each year,citing $800 million of works so far this financial year.

The digital train radio system became operational in 2016 after years of delays,and was the result of key safety recommendations from an inquiry into theWaterfall train disaster in 2003,which claimed seven lives.

The Rail Tram and Bus Union said trains drivers were set to be given handheld radios as a short-term contingency plan after last week’s system failure. “A system as critical as the NSW train network needs to have contingencies in place so that we can get things back up and running quickly if things go wrong,” a union spokesman said.

Transport Minister David Elliott has been approached for comment.

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