How the Severn Tunnel links beer, Scuba diving and the Oasis

Leaking water is in your beer, where the classic Oasis was born and one of the first Scuba dives.

It is also one of the most hostile places to lay a railway line.

More than 20 Olympic swimming pools of water are pumped from the Severn Tunnel every day – some of which is used in drinks such as Budweiser and Stella Artois, made just a few miles away.

You’d be forgiven for not realizing how difficult it is to make a train journey when traveling between Wales and England, in this impressive technique under England’s longest river.

It is the world’s longest underwater tunnel, a structure that took 13 years to build by hand – using picks, shovels, drills and dynamite – almost 140 years ago.

It’s a place where it feels like it’s always drizzling – and it’s the constant seepage of saltwater from the river above that makes even the most inhospitable neighborhood have a railroad track.

When it gets dark outside for the three minutes and 40 seconds spent cruising through the tunnel at 75mph (120km/h) on one of England’s busiest train routes, linking London and Bristol with south Wales, most people don’t forget the work they’ve done. done so they move.

It is the deepest part of the UK’s 22,000 mile (35,000km) rail network, and is where the railways have changed more than any other due to the corrosive saltwater atmosphere nearly 150ft (50m) below sea level.

That’s why the Severn Tunnel is there now closed for the longest time – except when it was electrified a few years ago – since it opened in 1886.

Usually about 200 trains a day pass through the four and a half mile (seven km) structure each day.

However, not now, because engineers have blocked 16 days until July 19 to renew the submerged south Wales border line, replacing all 66 rails, 10,800 sleepers and 22,000 tons of ballast that support the track.

“With the ingress of water, diesel fumes from the trains and the aggressive nature of the minerals in the tunnels, they attack the rails, so every five years now we have to renew the tracks,” said Brian Paynter of Network Rail.

“For sleepers and ballast, they are changed every 15 years. In England, it is probably the fastest we renew any rail because of the hostile environment.”

Outside the Severn Tunnel, track is usually replaced every 25 to 30 years.

Although 76.4 million bricks – often 10 layers deep surrounded by 1m (3 feet) of stone – withstand the waves of one of the most famous water bodies, the Severn still seeps through layers of tunnels.

Keeping the tunnel dry – beneath a fast-flowing river with the third highest tides in the world – has been a challenge since excavation began at the bottom of the Severn Estuary in 1873.

It is only the second tunnel to be attempted under water – but it is more than 13 times longer than the first, the 400m (1,300ft) Thames Tunnel in London, which opened in 1843.

There was no laser-guided radar equipment or tunnel-boring machine to build on this engineering feat in the Victorian era.

It’s all blood, sweat and tears with a lot of geology and math plus some trial and error.

“Engineers were made of other things that day,” Mr Paynter added.

“I can only imagine how difficult it was, with no computer, no phone, no laser, no sonar – they did an amazing job and 150 years later it’s still going strong.”

The tunnel and its close are about seven miles (11km) long so the line can dip almost 450ft below the lowest point of the Severn, but ensure that the gradient is gentle enough for express trains to pass through.

The work was difficult and slow, with pumps pumping out any water – but disaster struck six years into the build, when diggers hit an underwater source.

Workers were less than 119m (400ft) from connecting the two tubes when the tunnel was first flooded in 1879.

Construction was delayed for more than a year and could only resume after Alexander Lambert made one of the first scuba dives in history, using Henry Fleuss’ newly developed self-contained rebreather device, which allowed him to close the watertight doors.

The chief engineer of the Great Western Railway, Sir John Hawkshaw, also ordered the spring to be closed and the tunnel line aligned below to avoid further obstructions.

Floods had breached the tunnel several times, notably in 1883 and 1885, so engineers installed a larger permanent pump on the Welsh side.

However, until recently, the huge pump was working 24/7 to pump 20m gallons of water from the tunnel every day – with some coming in.

The tunnel cuts the journey time between Bristol and south Wales by around an hour – and is the fastest way to cross the estuary before first Severn road bridge opened in 1966.

It was the longest underwater tunnel in the world until 1987 and, for more than 100 years, it was the longest railway tunnel in England.

But keeping it operational and reducing delays is a huge task that requires constant attention – and each work program takes five years to plan and starts as soon as the previous cycle has finished.

But one delay in the tunnel in the 1990s gave Noel Gallagher time to write one of the most popular Oasis songs and Britpop songs of the 1990s.

Acquiesce, a fan favorite and Oasis set list staple for 15 years, has a musical beginning under the sea between England and Wales.

“I wrote the song on the train on the way to Loco Studios in south Wales for the Definitely Maybe sessions,” says Oasis songwriter Noel Gallagher.

“I was alone. I was stuck in the Severn Tunnel and I had an acoustic guitar. I was like ‘pass me the guitar, what does the word Acquiesce mean?'”

The tunnel was closed for 10 days last year for track replacement, this year it was closed for 16 days for the same around-the-clock work that will cost around £10m.

Water collecting channels have been added to the crown of the tunnel to reduce salt water dripping onto the tracks.

Ventilation fans have also been installed to create a constant breeze to create a better environment for steel tracks and electrical cables.

Each of the 66 lengths of new railway to be installed this July is larger than two football pitches at 215m (705ft) long and cost around £14,000 each.

Around 10,800 concrete sleepers, costing £90 each, will also be replaced.

“Some skeptics say you’re blocking the rail,” added Network Rail’s Mr Paynter.

“But I’m doing it for the better to make sure the network lasts and is safer. This is a temporary disruption, but if we don’t change the track, everything becomes life-expiring. It’s a short pain for a long gain.”