London’s Northern City Line has reached another milestone in Britain’s digital rail transition, as all trains on the route are now running with the latest European Train Control…
London’s Northern City Line has reached another milestone in Britain’s digital rail transition, as all trains on the route are now running with the latest European Train Control System (ETCS) software. The upgrade by Govia Thameslink Railway (GTR) and Siemens Mobility prepares the line for full integration into the East Coast Digital Programme.
GTR and Siemens have finished upgrading the entire fleet of 25 commuter trains on the Northern City Line to operate using ETCS Baseline 3, Release 2 (version 3.6.0), the newest generation of in-cab digital signalling. The update connects trains to the trackside via GPRS rather than the older GSM-R system, improving data capacity and paving the way for higher-frequency, more reliable services in one of London’s busiest commuter corridors.
The upgraded trains run between Finsbury Park and Moorgate, forming part of the government-backed East Coast Digital Programme (ECDP) — the first major deployment of ETCS on a British intercity route. The Northern City Line, which became the UK’s first signals-free commuter railway in May 2025, now also operates with the same baseline version that will be used across the East Coast Main Line in coming years.
In less than three months, Siemens and GTR engineers updated all 25 units of the Class 717 Great Northern trains, confirming that the software can be rolled out quickly and safely across other fleets. The system remains compatible with older ETCS baselines and conventional UK signalling, which means allowing mixed operation during the national transition.
‘Forging the way’ for national rollout
GTR’s Senior Programme Delivery Manager Aaron Meakin said the Northern City Line continues to lead the way in Britain’s digital transformation. “Once again, innovations delivered on the Northern City Line are forging the way for the introduction of in-cab digital signalling on the wider UK network,” he said. “By upgrading all our trains to operate with this updated version of the European Train Control System, we’ve proved the concept ready for its roll-out to other train fleets.”
The Northern City Line upgrade comes as part of the UK’s wider 10.2-billion-pound rail investment plan, confirmed in July under the government’s post-Spending Review infrastructure package. The programme funds several major projects, from the Transpennine Route Upgrade and East West Rail to new stations and regional electrification schemes. Crucially, it also secures further backing for the East Coast Main Line digital signalling rollout, which will extend the ETCS technology now tested in London to long-distance routes linking London, Leeds, Newcastle, and Edinburgh.
The government says the digital upgrade will cut delays by up to a third and support nearly 4,800 skilled jobs across the rail supply chain. Yet not all projects survived the review: parts of the Midland Main Line electrification and capacity works around York have been paused, and several regional improvements deferred.
