Blackheath Tunnel Upgrade

From Sunday 18 May to Sunday 27 July 2025 inclusive, the Blackheath tunnel between Blackheath and Charlton will close as Network Rail begins £10m of essential repairs to the 175-year-old Victorian-era structure.

The work this year, follows a 10-week closure last summer where 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 which normally run through the tunnel will be diverted via other routes during the 10 weeks.

Why is the work needed?

The work is needed because the one-mile-long tunnel, which opened in 1849, is prone to leaks and water damage. This is due to brickwork damage caused 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 1000 minutes of delay to Southeastern passengers.

Delaying the work into the future is not an option as the track and equipment in the tunnel would only deteriorate further causing an increase in delays and disruption to journeys.

Why is the work being done over 10 weeks? Why can’t it be done at weekends?

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.

A series of 10-week closures is needed because carrying out work 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 repair work.

The alternative would have been a year of weekend closures, causing significantly more inconvenience for passengers.

What are we doing?

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 essential track work carried out, including ‘wet bed’ removal – these are waterlogged sections of track that cause bumpy train rides for customers. These additional works will mean less disruption for passengers in the long term.

What are the benefits?

When the tunnel is repaired and water damaged infrastructure replaced passengers will benefit from fewer delays, fewer speed restrictions and improved reliability.

How will my journey be affected?

Around 4,000 passengers per week usually travel between Blackheath and Charlton via the tunnel.

To minimise disruption and keep passengers moving when work is taking place, services from Dartford to Cannon Street via Charlton and Lewisham will run 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, which will add around seven minutes to journeys.

Other services will be diverted along the Bexleyheath line.

There will be no rail replacement buses but you should be able to travel on selected TfL bus routes at no extra cost. We will provide more details here shortly.

A taxi can be provided for customers with accessible needs for travel between Blackheath and Charlton.

Get in touch

For more information call our National Helpline on 03457 11 41 41, visit our contact us page, or contact us on X @NetworkRailSE.