Passengers in south-east London are being reminded to plan ahead as the railway tunnel between Blackheath and Charlton will close for a second round of repairs next month. The railway will close from Sunday 18th May to Sunday 27th July 2025 as Network Rail carries out £10 million of repairs to the 175-year-old Victorian-era structure.

The work follows a 10-week closure in 2024, during which engineers cleaned soot from the tunnel lining, carried out detailed surveys and replaced thousands of bricks to stop water leaking into the tunnel and damaging the railway.

Services that normally run through the tunnel will be diverted via other routes.

The work is needed because the one-mile-long tunnel, which opened in 1849, is prone to leaks and water damage. The tunnel’s brickwork is affected by the freezing and thawing of rainwater which filters through the ground into the tunnel. While the tunnel is safe, the leaks and very wet conditions inside it damage track and electrical equipment, causing delays and speed restrictions.

Over the last year, faults in the tunnel have been the cause of around 1,000 minutes of delay to Southeastern passengers.

Scott Brightwell, Southeastern’s operations and safety director said: “We are working ever closer with our Alliance partner Network Rail to deliver better journeys, and these essential repairs will improve the safety and operation of the tunnel.

“I want to thank customers for bearing with us during the closure and there are a number of alternative travel options.

“We are running extra services on Woolwich line for connections to the Docklands Light Railway and the Elizabeth line.

“There are also extra services on the Bexleyheath line and your rail tickets can be used at no extra cost on some local bus routes. Full details are available on our website.”

Over the course of the entire programme of works, Network Rail will replace thousands of bricks and install a new tunnel lining to stop water leaking into the tunnel, which will be crucial for the reliable running of the railway long into the future.

Drainage systems will be rebuilt and track work carried out, including the removal of ‘wet beds’ – in other words, dealing with waterlogged sections of track that cause bumpy train rides for customers. The additional work means less disruption for passengers in the long term.

Passenger information

During the closure, services from Dartford to Cannon Street (via Charlton and Lewisham) will run instead via Greenwich, stopping additionally at Westcombe Park, Maze Hill, Greenwich, and Deptford. This offers the option to travel on the DLR from Greenwich to Lewisham, adding around seven minutes to journeys.

Other services will be diverted along the Bexleyheath line.

There will be no rail replacement buses, but passengers can travel on selected Transport for London bus routes at no extra cost. A taxi can be provided for customers with accessible needs for travel between Blackheath and Charlton.