The Blackheath Tunnel reopened on Monday (August 12), after a 10-week closure for essential repairs.

The 175-year-old tunnel underwent significant work to its brickwork to prevent water leaks that have been damaging the railway.

The £10 million investment aims to improve journeys for Southeastern customers by reducing delays and enhancing reliability.

With the tunnel now open, Southeastern has resumed its normal timetable, running four trains per hour between Dartford and Cannon Street via Charlton, Blackheath, and Lewisham.

During this phase of work, Network Rail and its partner, the Southern Integrated Delivery (SID), used a specialist industrial vacuum to clean years of soot build-up from the tunnel lining, a remnant from the days when steam trains passed through.

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More than 10,000 bricks were used to repair the tunnel lining, addressing the damage caused by years of freezing and thawing rainwater that had seeped through the ground.

Detailed structural and ground surveys were also conducted in preparation for further work planned for next year.

While the tunnel has remained safe, the leaks and wet conditions inside had been damaging the track and electrical equipment, causing delays and speed restrictions.

Over the past year, faults in the tunnel resulted in around 1,000 minutes of delays for Southeastern customers.

The Blackheath Railway Tunnel was opened on July 30, 1849, as part of the route connecting Blackheath and Charlton stations.

David Davidson, Network Rail’s Route Director for Kent, said: “We’re grateful to everyone’s patience while we’ve undertaken the work within Blackheath Tunnel over the last 10 weeks.

“We’re in the process of renewing everything within the tunnel, which includes replacing the track.

“That means we’ll need to return to Blackheath to complete this work over the next few years so that we can keep this Victorian-era structure in the best possible condition.

“We will now assess the further repair work needed for next year and will keep passengers and stakeholders informed on next steps.”

Scott Brightwell, Southeastern’s operations and safety director said: “The repairs that have been carried out in the tunnel will help to deliver better journeys for our customers, and I want to thank them for bearing with us while it was closed over the summer.

“With the tunnel re-opening we can run our normal timetable again, and at the busier times there will be four trains per hour between Dartford and Cannon Street via Charlton, Blackheath, and Lewisham.

"Please check before you travel from Monday, August 12."