A FAULT in the nationwide radio system used by train drivers and signallers caused significant delays across the UK rail network on Friday morning.
National Rail confirmed the issue involves the GSM-R system, which facilitates communication during emergencies.
Services on the Elizabeth line, Gatwick Express, Great Northern, Southern, South Western Railway, Thameslink, Southeastern, and ScotRail have been affected, the BBC reported.
Travel to and from major transport hubs, including London Paddington and Victoria, has also been disrupted.
The Rail Safety and Standards Board Rule Book mandates that trains cannot exceed 100mph (160km/h) or 60mph (100km/h) in affected areas during a radio failure.
National Rail advised passengers to expect cancellations and delays of up to 15 minutes on Southern, Thameslink, and Great Northern services. While most passengers can use their usual routes, some short-notice cancellations are possible. The disruption is expected to continue until 12:00 GMT.
The Gatwick Express is currently operating only between London Victoria and Gatwick Airport, excluding Brighton. Elizabeth line services between Reading and Heathrow Airport are also impacted. ScotRail noted earlier disruptions but said its services are now running normally.
The GSM-R system operates independently of commercial mobile networks, using a dedicated infrastructure of masts and communication devices. A rail industry source told the BBC that "the system isn't connecting easily," though a workaround exists, albeit time-consuming to implement.
National Rail stated that the cause of the fault is under investigation. Passengers have been advised to check schedules before travelling.
