Digital signalling upgrade completes Portsmouth Direct modernisation
Alstom and Network Rail complete a major signalling and level-crossing upgrade between Farncombe and Petersfield as part of the Portsmouth Direct programme.
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Alstom has completed a £49 million signalling contract on the Farncombe to Petersfield section of the Portsmouth Direct line, marking the final stage of Network Rail’s £129 million multi-year upgrade to modernise signalling and track infrastructure between London and Portsmouth.
Context of the cooperation
The Portsmouth Direct line is one of the UK’s busiest mixed-traffic routes and includes infrastructure dating back more than 150 years. Ageing signalling assets and legacy control systems required renewal to improve reliability, safety, and maintainability while preparing the route for future digital railway technologies.
The Farncombe to Petersfield project was delivered under the Major Signalling Framework Agreement (MSFA) for Network Rail’s Southern Region, secured by Alstom in 2020. The programme focused on replacing life-expired equipment and consolidating control into a modern operating environment.
Technical solution and responsibilities
Alstom was responsible for the design, installation, testing, and commissioning of new signalling and level-crossing systems, working in partnership with Network Rail and a wider supply chain.
Key elements of the upgrade included the renewal of eleven level crossings, the deployment of Alstom digital interlockings, and the migration of signalling control from three local signal boxes to Network Rail’s Basingstoke Rail Operating Centre. Track circuits were replaced with axle counters, delivering approximately 50% power savings across the project area while improving safety for trackside maintenance staff.
Alstom also introduced its SmartIO object controller technology, which connects trackside equipment directly to central control systems. The associated equipment housings operate without air conditioning, heating, or domestic power supplies, reducing both operational energy use and lifecycle costs.
Deployment during possession
During a nine-day line closure between Guildford and Havant in November 2025, Alstom engineers tested and commissioned 90 new LED signals, installed more than 30 km of new cabling, and brought 17 new SmartIO controllers and equipment buildings into service.
Level-crossing works included the introduction of obstacle-detection technology, CCTV installations at selected sites to improve visibility for signallers, and miniature stop-light systems at foot crossings to enhance safety for pedestrians and road users.
Results and operational impact
The works were completed within the planned possession window, with testing and commissioning successfully concluded to enable the line to return to service. The upgraded infrastructure improves signalling reliability, increases asset performance, and reduces maintenance intervention requirements, contributing to more resilient passenger and freight operations.
The Farncombe to Petersfield contract represents the final delivery phase of Network Rail’s Portsmouth Direct Upgrade, which has introduced modern signalling and safer level crossings along the route between London Waterloo and Portsmouth Harbour. The programme establishes a digital-ready foundation to support future railway enhancements while reducing the likelihood of disruptive closures.
Through this project, Alstom and Network Rail have demonstrated how coordinated planning, modern digital signalling technologies, and concentrated delivery windows can modernise complex legacy rail infrastructure while maintaining safety and operational continuity.
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