Network Rail will push ahead with the next stage of modernisation on the Portsmouth Direct Line later this month, with buses replacing trains between Havant, Fareham and Portsmouth Harbour from Saturday 28 March to Thursday 2 April.

This phase brings an additional £120 million investment into a multi‑year programme to modernise the route. By 2028, signalling will move from the Havant Area Signalling Centre to the Basingstoke Rail Operating Centre, improving communication between signallers and speeding up responses to incidents to deliver a more reliable railway.

It follows the first phase completed in 2025, which invested £129m to upgrade signalling between Farncombe and Petersfield, improving the reliability and safety of services between London and Portsmouth.

During the six‑day closure, engineers will upgrade the signalling system and strengthen key infrastructure in the Havant and Portsmouth area. The work includes repairs to cable troughing between Farlington and Cosham to better protect signalling equipment; structural repairs to Portcreek Viaduct, which connects the mainland with Portsmouth on Portsea Island; renewing 48 wheel timbers through Platform 2 at Portsmouth & Southsea; replacing a further 14 wheel timbers outside Portsmouth Harbour; and tamping to improve track alignment across the Portsmouth area. In total, around 1,378 hours of work will be carried out.

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Train services will change throughout the works. South Western Railway trains to and from Portsmouth Harbour will start or terminate at Havant or Fareham. Southern trains to and from Portsmouth Harbour will start or end at Havant, with services for Portsmouth & Southsea diverted to Bognor Regis; Southern trains between Brighton and Southampton will run as normal. Great Western Railway services to and from Portsmouth Harbour will start or finish at Fareham.

Replacement buses will operate five times per hour between Havant and Portsmouth Harbour, calling at Bedhampton, Hilsea, Fratton and Portsmouth & Southsea, and twice per hour between Fareham and Portsmouth Harbour, calling at Portchester, Cosham, Hilsea, Fratton and Portsmouth & Southsea.

Tom McNamee, Infrastructure Director, speaking on behalf of Network Rail and South Western Railway, said: "Following the successful completion of the first phase of upgrades last year, we are now starting the next stage of modernising signalling on the Portsmouth Direct Line.

"Some of the signalling equipment in the Havant area is ageing and is increasingly prone to faults. Replacing it with modern technology will improve reliability and help reduce delays for passengers travelling to and from the south coast.

"Some of this work can only take place when trains are not running, so access is carefully planned to complete as much of the improvements as possible while minimising disruption."

Further line closures are planned around the late May Bank Holiday, with engineers set to return again in the autumn.