O2 & Cellnex boost mobile coverage on Brighton Main Line

SOFIAH NICHOLE SALIVIO

News Editor

Cellnex and O2 have signed an agreement to improve mobile coverage on the Brighton Main Line, one of Britain’s busiest commuter rail corridors.

Under the deal, O2 will use Cellnex infrastructure to extend mobile connectivity, including 5G, along the route between London, Gatwick Airport and the south coast. The rollout will take place in phases across the line and at major stations including London Victoria, London Bridge and Clapham Junction.

The Brighton Main Line carries more than 300,000 passengers on weekdays and supports 1,700 train movements a day. About 50,000 of those journeys are to and from Gatwick Airport, according to the companies.

The agreement adds O2 to a programme that already includes Three UK, which signed up in 2023. Cellnex is building the network as a neutral host system, allowing multiple mobile operators to use shared infrastructure rather than install separate equipment.

The route has long been difficult for mobile coverage because of tunnels, deep cuttings and older station structures. These conditions have contributed to persistent signal gaps for passengers travelling between central London, major commuter areas and Gatwick Airport.

Route upgrade

The infrastructure was developed with Network Rail under a 25-year contract awarded in 2021. Once fully activated, the system is intended to deliver mobile connectivity across 99% of the 108km corridor.

The build programme has run for three years and involved more than 129,000 working hours and more than 11,000 worker entries at stations and trackside locations. Installed equipment includes 130km of fibre, four base station hotels for mobile operator equipment, 39 distributed antenna systems in tunnels and along the track, dedicated station distributed antenna systems at London Bridge, London Victoria and Clapham Junction, and 16 macro sites along the route.

The shared model is designed to lower costs for operators and reduce the amount of physical infrastructure needed on the railway. Cellnex is also seeking wider participation from other mobile networks so more passengers can use the improved coverage regardless of provider.

For commuters, the upgrade addresses a familiar problem on one of the capital’s busiest rail lines. Mobile connections on parts of the route have historically dropped during calls, streaming and app use, particularly in tunnels and busy station areas.

Steve Cray, Managing Director, Cellnex UK, said: “Regular railway passengers will understand the frustration of losing signal mid-conversation or spending whole journeys with buffering videos. With O2 now on board, many more passengers are going to notice the difference on one of the UK’s most important commuter routes. This collaboration stands as one of the most significant end-to-end telecommunications infrastructure deployments on the British railway so far, and we are proud to be setting a new standard for the UK’s entire rail network.”

Operator demand

The addition of O2 points to growing demand among network operators for shared mobile systems on transport routes where standalone deployment can be difficult and costly. Rail corridors present technical and operational challenges because work must be carried out around live services and within constrained infrastructure.

O2 linked the Brighton Main Line deal to its wider network investment programme, saying the agreement would improve both coverage and capacity for customers travelling between the coast and the capital.

Robert Joyce said: “Our £700m Mobile Transformation Plan is focused on delivering reliable connectivity in the moments that matter most, and railway lines are a key part of that. By working with Cellnex to improve connectivity along the Brighton Main Line, we’ll be bringing improved coverage and capacity to customers travelling from the coast to the capital over the coming months.”

Network Rail said the project had required years of coordination on a route that remains in constant use. The infrastructure owner described the work as part of a broader effort to modernise the passenger experience on a line that is central to commuting into London.

Richmond said: “Passengers on the Brighton Main Line deserve connectivity that matches the importance of this route, and our long-term partnership with Cellnex is transforming what has historically been one of the most technically demanding corridors for mobile coverage into a showcase for modern railway connectivity. A huge amount of collaboration has gone into this project over the last few years to support the infrastructure on a railway that is constantly operational. With O2 now on board, even more passengers will soon experience the benefits of this investment every time they travel.”