A £49 million project to upgrade the signalling on the line between Farncombe and Petersfield in Hampshire has been completed, after a nine-day closure during which engineers from Alstom tested 90 new signals and commissioned 17 new equipment buildings.

The work also marked the completion of a £129 million upgrade to modernise the signalling and track between London and Portsmouth on the Portsmouth Direct line between London Waterloo and Portsmouth Harbour.

The project is part of a Major Signalling Framework Agreement for the Southern Region, being carried out by Alstom in partnership with Network Rail. The work included:

• Upgrading 11 level crossings.
• Transferring control of the area’s signalling from three manual signal boxes to a Rail Operating Centre at Basingstoke.
• Implementing digital interlocking to increase reliability, performance, and capacity.
• Replacing track circuits with axle counters.

In November 2025, the line between Guildford and Havant was closed for nine days to enable engineers to test 90 new LED signals, install over 30 km of new cable, and commission 17 new SmartIO object controllers and equipment housings. SmartIO is a proprietary Alstom system that connects trackside equipment, including signals and points, directly to a central control system.

Other work during the project included installing obstacle-detection technology at seven level crossings; CCTV at two crossings to improve safety for road users and provide signalers with clearer visibility of the lines; and miniature warning stop lights at two foot crossings.

“Alstom has been proud to partner on one the most significant investments ever made on the Portsmouth Direct line, replacing life-expired equipment with cutting-edge technology that will transform reliability and performance for years to come. By introducing digital-ready signalling and advanced level crossing systems, we’ve not only modernised a route that dates back more than 150 years, but we have also created a foundation for the digital railway of the future. I’m incredibly proud of the team’s achievement in delivering this complex programme safely and efficiently. Alstom colleagues completed the work during a nine-day closure with zero injuries – everyone went home safe. This success reflects the strength of our partnership with Network Rail and our supply chain, along with our shared commitment to innovation, sustainability and passenger experience.”

Emmanuel Henry, Digital and Integrated Systems Managing Director UK and Ireland at Alstom