Ahead of repair work to the Blackheath railway tunnel starting on Sunday, Network Rail is reminding passengers to plan journeys ahead of time.

From May 18th until July 27th 2025, the line between Blackheath and Charlton will be closed, meaning that services will be diverted via Greenwich and Bexleyheath.

Over the 10 weeks, Network Rail engineers will be carrying out £10 million of essential repairs on the Victorian structure.

The tunnel was previously closed in June 2024 for some maintenance, including cleaning, surveying and replacing some bricks.

They noted some significant leaks and water damage, which did not affect the safety of the tunnel; it did, however, affect service reliability. The tunnel reopened 10 weeks later in August.

They will be replacing numerous bricks and installing a new lining to prevent further leaking. Additionally, they will be carrying out work on the track bed to make journeys smoother,

Southeastern’s timetable change also starts on the same day, so only some services will be affected.

Services that should pass through the tunnel will be diverted, which also means there will be fewer Cannon Street services that will stop at St John’s and New Cross.

The work to fix the tunnel should stop any water damage issues and prevent last year’s 1,000 minutes of delay, which were directly caused by the tunnel.

“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. These essential repairs will improve the safety and operation of the tunnel. 

“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. 

“I want to thank customers for bearing with us during the closure, during which 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, and there are also extra services on the Bexleyheath line. Rail tickets can also be used at no extra cost on some local bus routes, with full details available on the Southeastern website.”

David Davidson, Network Rail’s Kent route director