Analysis | When one outage stops an entire rail network
The statewide shutdown left thousands of passengers stranded and raised important questions about the resilience of Victoria's regional rail network.
The fallout from Telstra’s outage on Wednesday continues, with Telstra CEO Vicki Brady expected to be called before the Senate’s Triple Zero inquiry after more than 600 emergency calls failed to connect. The broader economic impact of the disruption is also expected to be significant.
Locally, the most obvious impact was the complete shutdown of the regional rail network as V/Line services across the state ground to a halt, leaving thousands of passengers stranded and plans thrown into disarray.
Inevitably, the question being asked is simple: if one telecommunications outage can stop an entire railway, is the system resilient enough?
The Nationals’ Member for Euroa, Annabelle Cleeland, summed up the frustration felt by many regional Victorians, saying: “Regional Victorians deserve better than excuses. They deserve a government that plans for failures before they happen; not after.”
Member for Northern Victoria Gaelle Broad asked a similar question from a different angle.
“If a telecommunications outage can bring the entire regional rail network to a standstill, the government needs to explain why there is no system in place to keep people moving,” she said.
Premier Jacinta Allan has instead directed her criticism towards Telstra.
“Telstra should compensate Victorians and help make sure it never happens again,” she said.
The Premier has announced V/Line will reimburse passengers who incurred additional costs because of the disruption, while the Victorian Government will fund two days of free travel on V/Line.
As a privately owned telecommunications company regulated under Commonwealth law, whether Telstra agrees to the Premier's request will ultimately be a matter for the company.
So what actually happened? More importantly, could it happen again?
According to Telstra, the outage was caused by a software fault affecting data centre equipment rather than human error.
That explains the outage.
It doesn’t explain why Metro trains kept running while every V/Line service stopped.
The answer comes down to how the two rail networks operate.
Metro runs a heavily signalled suburban railway. Trains are continuously tracked by dedicated signalling systems operating over a private communications network. Even if other communications are interrupted, those signalling systems continue telling trains where they are, controlling signals and maintaining safe separation between services. Delays might occur, but the railway can generally keep operating.
Regional Victoria is a very different story.
V/Line manages more than 3,000 kilometres of railway, much of it through sparsely populated areas with long stretches of single track and relatively few signals. Across much of the regional network, train controllers rely on direct communications with train crews to issue movement authorities or otherwise authorise and manage train movements, particularly on long sections of single track.
Those communications aren’t just helpful, they are a critical part of the railway’s safety system.
When the Telstra outage interrupted those communications, controllers could no longer reliably issue movement authorities or communicate with train crews. Without those safety-critical communications, V/Line could not continue operating trains under its approved safeworking procedures.
The railway is designed to do exactly what it did this week. It stops.
That might sound frustrating, but it is also reassuring. Railways are deliberately engineered to fail safely. If there is uncertainty about train movements or the communications needed to authorise them, services are suspended until operators can confirm it is safe to proceed.
So, did V/Line make the wrong decision?
Almost certainly not.
Once those communications were lost, suspending services was almost certainly the only safe operational response available.
The more interesting question is whether the communications systems supporting those safety systems should themselves be more resilient.
So what’s the solution?
Like many complex problems, there isn’t a simple one.
V/Line’s communications systems already include backup arrangements. What this outage exposed is that both the primary and backup communications ultimately relied on the same underlying telecommunications network. When that network experienced a major failure, both were affected.
That is the vulnerability now under scrutiny.
The most practical solution isn’t rebuilding Victoria’s entire rail network.
Instead, it would involve making the communications network itself more resilient through greater independence between primary and backup systems, more diverse communications paths or alternative ways of maintaining train communications if one carrier experiences a major outage.
Those improvements would still come at a cost, but nowhere near the billions required to completely redesign Victoria’s regional railway.
The more ambitious alternative would be progressively installing Metro-style signalling across much larger sections of the regional network.
Technically, it would reduce reliance on voice communications.
Financially, it’s a different story.
With more than 3,000 kilometres of regional railway, many carrying only a handful of passenger services each day, that level of investment would likely cost hundreds of millions, if not billions, of dollars and take many years to complete. It’s difficult to justify for much of the network.
Which is why the most feasible response is strengthening the communications systems that keep it running safely.
Ultimately, this week’s outage was about more than Telstra.
And it was about more than V/Line.
It exposed a broader question about how much resilience we expect from the critical infrastructure regional Victorians rely on every day.
The railway did exactly what it was designed to do when communications were lost and failed safely.
The question now is whether Victoria is comfortable with a situation where the failure of a single telecommunications network can still bring an entire regional rail system to a standstill.
Editor's note: This analysis is based on publicly available information, including statements from the Victorian Government, Telstra and local Members of Parliament, together with publicly available information about Victoria's regional rail network and railway operations.