Rail passengers in south-east London are being urged to plan ahead as Network Rail begins a £10 million programme of essential repairs to the historic Blackheath railway tunnel.
The 175-year-old Victorian-era tunnel will close for 10 weeks from Sunday 18 May to Sunday 27 July 2025, affecting Southeastern train services across the region.
The closure follows a similar 10-week shutdown in 2024, during which engineers cleaned soot, conducted detailed surveys, and replaced thousands of bricks to address water damage. This year’s works will go further—replacing more brickwork, installing a new tunnel lining, and rebuilding drainage systems to prevent leaks that have long plagued the tunnel.
The tunnel, which opened in 1849, is prone to water ingress that damages track and electrical systems, leading to delays and speed restrictions. Over the past year alone, faults in the tunnel have caused around 1,000 minutes of delays for Southeastern passengers.
During the closure, train services will be diverted via Greenwich and Bexleyheath, with fewer Cannon Street services calling at St Johns and New Cross. The closure coincides with Southeastern’s timetable change, so passengers are advised to check journey times carefully during this period.
David Davidson, Kent Route Director at Network Rail, said:
“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."
The work will also include the removal of ‘wet beds’—waterlogged sections of track that cause uncomfortable, bumpy rides. Once complete, passengers can expect fewer delays, improved ride quality, and more reliable services through the Blackheath corridor.
While the short-term disruption will affect daily commutes, the long-term benefits are clear. The repairs will help preserve the structural integrity of the tunnel and reduce the need for future closures, ensuring smoother, safer journeys for years to come.
Image credit: iStock
