Network Rail has given advance warning that train services through Blackheath will be severely disrupted from mid-May until the end of July because of essential repairs to Blackheath Tunnel.

The line between Blackheath and Charlton will be closed from Sunday, 18th May to Sunday, 27 July 2025 to allow Network Rail to carry out £10 million of essential repairs to the 175-year-old Victorian-era structure.

In the last year, services have accumulated around 1,000 minutes of delays because of faults in the tunnel. During the closure, services that normally use the tunnel will be diverted via other routes.

Last summer, Network Rail also gave warning that the line would be closed for ten weeks so that engineers could carry out detailed surveys of the tunnel, clean soot from its lining, and replace thousands of bricks to stop water leaking into it and damaging the railway lines.

Blackheath Tunnel is one mile long and opened in 1849. It is now succumbing to leaks and water damage caused by the tunnel’s brickwork being affected by rainwater freezing and thawing, and filtering through the ground into the tunnel.

Although the tunnel is safe for the passage of trains, leaks and very wet conditions inside the tunnel have the potential to damage track and electrical equipment, which will cause delays and speed restrictions.

Southeastern is working with Network Rail to deliver better journeys, and these essential repairs will improve the safety and operation of the tunnel.

There are alternative travel options, including extra services on the Woolwich line for connections to the Docklands Light Railway and the Elizabeth line, and extra services on the Bexleyheath line.

Rail tickets can also be used at no extra cost on some local bus routes, and full details are available on Southeastern’s website.

“We know there’s never a good time to close the railway, and that changes to services for a 10-week period is a long time. We are carrying out the repairs over a series of 10-week closures because working in cramped and narrow tunnels is incredibly difficult. If traditional weekend working was used engineers would spend at least 50% of a weekend bringing materials and plant in and out of the tunnel, leaving limited time for actual work. We are sorry for the inconvenience caused by the closure, but this is a long-term project and this will be the last closure until we are back in to finish over summer 2027. When the tunnel is repaired with water-damaged infrastructure replaced and the tunnel waterproofed, passengers will benefit from fewer delays, fewer speed restrictions and improved reliability.”

David Davidson, Network Rail’s Kent route director