Successful high-speed testing has been completed on upgraded digital signalling software for Thameslink’s Class 700 fleet, marking another major step towards the rollout of in-cab signalling on the East Coast Main Line (ECML).
The trials, carried out during two overnight test sessions in April and May, involved a Thameslink Class 700 train operating through the central London core section between London Bridge and St Pancras using the latest European Train Control System (ETCS) version 3.6.0 software.
The Class 700 fleet, made up of 115 trains, is the largest passenger fleet included in the government-funded £1.4 billion East Coast Digital Programme (ECDP), which aims to replace traditional lineside signals with digital in-cab signalling technology.
The testing was delivered jointly by Govia Thameslink Railway (GTR), Network Rail and Siemens Mobility, with work scheduled carefully to avoid disruption to passenger services.
GTR is currently the UK’s only operator already using ETCS 3.6.0 in live passenger service through its Class 717 fleet on the Northern City Line. The latest trials were designed to ensure the upgraded software integrates correctly with the existing train systems while preparing the fleet for future deployment on the ECML.
The upgraded ETCS system allows trains to communicate with trackside infrastructure using GPRS-based packet switching technology, improving flexibility and operational performance on busy routes such as the East Coast Main Line.
Passenger services using ETCS on the ECML between Welwyn Garden City and Hitchin are expected to begin later this year, initially with Class 717 units. Migration of the Class 700 fleet is currently planned from 2027 onwards.
The software upgrades are also expected to support future digital signalling deployment on the Brighton Main Line and Midland Main Line.
Aaron Meakin, GTR’s Head of ERTMS Onboard, said the testing built on the operator’s growing experience with digital railway systems.
“We’re extremely proud of the teams delivering this testing, who worked extremely hard to ensure it was completed on time and safely in a very complex and critical environment, with minimal impact to our customers,” he said.
Network Rail’s ECDP Access Integration Lead Ricky Barsby described the work as “a vital step” in preparing the UK’s largest passenger fleet for digital migration.
Meanwhile, Siemens Mobility said the upgraded software would help support a more reliable, connected and sustainable railway for both passenger and freight operators on the ECML and beyond.
