How does a Telstra outage bring down trains? A telco expert explains

Australians experienced a significant disruption to their daily routines when a nationwide outage struck the Telstra network, the largest telecommunications provider in the country. The outage began around 4:30 am on Wednesday and lasted well into the early hours of Thursday, causing widespread effects beyond just mobile phone users. Public transportation systems, including train services in Victoria and New South Wales, faced severe disruptions. The Victorian regional train operator, V/Line, was forced to suspend services across all its lines, leaving commuters stranded and businesses facing operational challenges. In addition to the impact on train schedules, other critical services such as EFTPOS payments, taxi payment systems, and even electric vehicle charging platforms like Chargefox were affected. Reports indicated that emergency services, specifically Triple Zero calls, were also impacted, echoing similar issues seen during a previous Optus outage. The extent of the disruption highlights the deep integration of mobile networks into modern infrastructure. Trains, in particular, rely heavily on mobile connectivity for safe and efficient operations. Each train is equipped with roof-mounted antennae that facilitate communication with control centers. These antennae operate on frequency channels shared with mobile networks, allowing for real-time exchange of vital information. This includes the train's location, speed, arrival times, and any necessary adjustments to the schedule. Such data is crucial for maintaining safety and ensuring smooth travel. Additionally, these antennae support passenger services, enabling internet access and ticket management onboard. Without this connectivity, the ability to manage and monitor train movements becomes severely compromised. When the Telstra network went offline, it effectively severed the link between trains and their control centers. As a result, trains lost the capability to transmit essential information, including alerts regarding delays, cancellations, or route changes. This lack of communication poses serious risks, as it prevents operators from making timely decisions to address potential hazards. Furthermore, trains regularly send diagnostic data—such as engine and braking performance—to maintenance teams. Without this data, identifying and resolving mechanical issues becomes significantly more challenging. While trains could theoretically continue operating without mobile networks, as they did prior to the adoption of modern communication technologies, the absence of real-time monitoring compromises safety and reliability. The reliance on Telstra for critical railway communications underscores the vulnerability of infrastructure dependent on single service providers. The Australian Rail Track Corporation (ARTC), responsible for managing over 9,600 kilometers of rail track across several states, upgraded its train-to-network communications to 4G on the Telstra network in 2024. Similarly, VicTrack, which operates V/Rail, also utilizes the Telstra network, with ARTC serving as one of its key transport partners. This dependency means that any technical failure within the Telstra network directly impacts the functionality of these rail systems. While most train networks have contingency plans, such as satellite communication, these alternatives offer lower bandwidth and slower response times compared to terrestrial mobile networks. Consequently, the effectiveness of these backups is limited, especially in high-speed environments where constant connectivity is essential. The outage raises important questions about redundancy and resilience in critical infrastructure. Given that trains travel at high speeds, relying on a single mobile network leaves them exposed to disruptions. Some routes may depend solely on one service provider, meaning that any interruption in that provider's service affects the entire segment of the route. Financial considerations often play a role in determining the extent of mobile coverage, particularly in remote and rural regions where deploying multiple networks may not be economically viable. As a result, train operators must carefully consider diversifying their network options to avoid placing too much reliance on a single provider. Telstra continues to investigate the cause of the outage, though no definitive explanation has yet been released. The incident has prompted discussions among industry experts and regulators about the need for greater redundancy and alternative communication solutions. Moving forward, stakeholders are likely to scrutinize the current infrastructure and explore ways to enhance the resilience of both telecommunications and transportation systems. Until then, the lessons learned from this outage will serve as a reminder of the interconnected nature of modern society and the importance of robust, diversified infrastructure.