Hundreds of thousands of rail travellers experienced delays of an hour or more after the system that enables train drivers to communicate with signallers failed. The system in question is the Global System for Mobile Communications-Railway, commonly known as GSM-R. Network Rail describes it as a digital, secure, and dependable communications platform between drivers and signallers.
What is GSM-R?
GSM-R was introduced between 2007 and 2014 at a cost of £1.9 billion. Its purpose was to enhance safety and reduce costs by replacing a patchwork of outdated and inefficient legacy systems that were expensive to maintain. The technology combines standard mobile phone technology with a customised telecommunications network designed specifically for railway operations.
Why is it important?
Without GSM-R, drivers can lose contact with signallers when their trains are in deep cuttings or tunnels. Network Rail states that GSM-R improves safety for drivers, maintenance teams, and passengers. It also eliminates the need for drivers to leave the train in the event of a problem. The infrastructure operator adds that this helps increase safety, reduce delays, and improve performance, ultimately providing a better experience for passengers.
Key safety feature: Railway Emergency Call
A notable feature of GSM-R is a large red button that triggers a Railway Emergency Call. This can bring all trains in the local area to a halt. However, during a knife attack on an LNER train travelling from Peterborough to London King's Cross in November 2025, the driver deliberately chose not to activate this emergency call. Activating it would have stopped the train with an attacker on board in a location with no easy access for emergency services. Instead, the driver, Andrew Johnson, a 17-year Royal Navy veteran, contacted a signaller and requested an unscheduled stop at Huntingdon station. The attacker was subsequently apprehended, and injured passengers and crew received treatment.
Part of the GSM-R system failed in December 2024, affecting train operators nationwide. For more information on passenger rights during delays, see related articles.
