A BUSY railway tunnel has re-opened after a major £10 million renovation.
Repair works were carried out to tackle leaks and water damage in the structure.
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London commuters saw an end to disruption as the tunnel, located in the south-east of the city, reopened this week.
Southeastern trains between Charlton and Blackheath have resumed service from Monday, July 28.
Routes once again run through the mile-long Blackheath tunnel, after being diverted via Greenwich during the second such closure within a year.
Project details
Network Rail said the extensive repair work saw thousands of bricks replaced, new lining added, and drainage systems rebuilt.
David Davidson, Network Rail’s chief operating officer for south eastern railway, spoke about the revamp.
He described it as “groundbreaking”, adding that reliability would be increased by the strengthening and waterproofing work.
The tunnel, which first opened in 1849, had been closed since Tuesday, May 27.
“Savings from this approach are estimated to be around £10 million and this can be reinvested across the network to deliver more improvements that will keep passengers moving,” the rail rep said.
“Last summer, engineers cleaned soot from the tunnel lining, carried out detailed surveys, and replaced thousands of bricks to stop water getting in.
“This year a new tunnel lining will be installed, drainage systems rebuilt, and essential track work completed – including the removal of the waterlogged sections known as wet beds.”
Innovative works
The Victorian-era tunnel has undergone a pioneering strengthening and waterproofing process.
It is believed to be the first of its kind in the UK and potentially the world.
Engineers injected expansive grout into the pockets of sand and gravel surrounding the tunnel to help strengthen the ground.
This innovative technique works by knitting and compressing the loose material tightly together.
Another layer of grout was then applied to the back of the tunnel lining to waterproof the worst-affected areas.
Scope of the repair works
The £10 million engineering programme included:
- Waterproofing via expansive grout injection around the tunnel shell and lining.
- Replacement of thousands of bricks.
- Rebuild of drainage systems and removal of wet‑bed areas.
- Track realignment and general infrastructure renewal
This helped to preserve the brickwork and track, as well as signalling and other railway equipment in the tunnel for years to come.
The techniques trialled and used successfully in the Blackheath tunnel during this closure are set to be replicated across other parts of the rail network.
More on rails
A new £3 billion fleet of more than 90 air-conditioned underground trains has been delayed for another year.
And a small English town is set to open a new £42 million train station that will reopen key link shut for over 60 years.
Britain’s busiest railway will be shutting down for three weeks next month for a £20 million demolition.
Plus, a new £15 million train station linking tiny town to three major destinations has been unveiled in a new satellite photo.
And an English train station is set to shut for two years ahead of a major £11.5 million revamp.
