Underground (Miscellaneous: Tunnels, Roads, Bunkers Etc.)

[Victory]

* Mods I know there is an existing thread for these type of stories, please move this to that thread as I could not find it, thanks.

A man called Freddy Goodhall has found tunnels under his home.
He thinks they were used by serving staff in the 19th century.

https://metro.co.uk/2021/09/15/man-...els-and-hidden-rooms-in-family-home-15262607/

 

[Mr. Banooka]

The Chigg has been looking for Kenny again.

 

[TheLeeds]

I read somewhere that when the Victoria Line was built in the 1960's it was routed directly under Buckingham Palace to provide the Queen with an emergency escape route.

I can't be bothered to read 34 pages to check if someone has already said this.

But anyway, if you look on the CartoMetro map of the railways under London, it does look possible that the VIctoria Line passes under, or very close to Buckingham Palace. Zoom in on the map between Green Park and Pimlico and you can see the direction of the tracks.....

https://cartometro.com/cartes/metro-tram-london/

 

[hunck]

I can't be bothered to read 34 pages to check if someone has already said this.

But anyway, if you look on the CartoMetro map of the railways under London, it does look possible that the VIctoria Line passes under, or very close to Buckingham Palace. Zoom in on the map between Green Park and Pimlico and you can see the direction of the tracks.....

https://cartometro.com/cartes/metro-tram-london/

I have my doubts - I can’t imagine Her Maj getting on the tube - to where?

Any sign of trouble I think she’d vacate in advance by other means.

 

[RaM]

I have a vague memory of a tv program that pointed out that tube lines
did have a tendency to run under buildings of interest and talked of the
likelihood of bolt holes to a get out of London fast route if the excrement
hit the fan, it was some years back and I cant remember anything more
about it.

 

[Trevp666]

A large amount of the earlier London Underground lines were built by private companies using the cheapest method possible, which at the time was 'cut-and-cover'. This meant that they followed existing roads, and only a few feet deep. Hence it is quite likely that a lot of those lines will run past the fronts of many important addresses.
Here is an illustration of the method being employed 150 years ago.

 

[IbisNibs]

And on the other side of the pond, we have La Kiva, the underground bar (linked pic by Ivan Collins):
https://texashighways.com/eat-drink/dining/la-kiva-restaurant-helps-heal-the-terlingua-community/

I've never been, but would face Texas in order to go there.

On the banks of Terlingua Creek, a ramp leads down into La Kiva, one of the most famous bar/restaurants in the Big Bend area. In Hopi culture, a kiva is an underground chamber used for religious and political meetings. But this kiva is a meeting place for the dreamers, lost souls, river guides, and tourists who are drawn to the old mining town and surrounding desert.

 

[James_H]

Welbeck abbey (and particularly the 5th duke of Portland [1800-1879]) are interesting areas of research, the 5th Duke apparently punished his staff by making them skate until exhausted on his own ice rink and “When the duke died, his heirs found all of the above ground rooms devoid of furniture except for one chamber in the middle of which sat the duke’s commode. The main hall was mysteriously floorless. Most of the rooms were painted pink. The one upstairs room in which the duke resided was packed to the ceiling with hundreds of green boxes, each of which contained a single dark brown wig.” *.

Stumbled across this man while perusing the wikipedia article on hobby tunnelling (supercomputer pioneer Seymour Cray was among many who dug holes to unwind).

More on John* Bentick, 5th Duke of Portland:

The Duke was a highly eccentric character who went out of his way to avoid contact with other human beings.

The duke was highly introverted and well known for his eccentricity; he did not want to meet people and never invited anyone to his home. He employed hundreds through his various construction projects, and though well paid, the employees were not allowed to speak to him or acknowledge him. The one worker who raised his hat to the duke was promptly dismissed. The tenants on his estates were aware of his wishes and knew they were required to ignore him if they passed by. His rooms had double letterboxes, one for in-coming and another for out-going mail. Only his valet was permitted to see him in person in his quarters—he would not even let the doctor in, while his tenants and workmen received all their instructions in writing.

...

He ventured outside mainly by night, when he was preceded by a lady servant carrying a lantern 40 yards (37 m) ahead of him. If he did walk out by day, the duke wore two overcoats, an extremely tall hat, an extremely high collar, and carried a very large umbrella behind which he tried to hide if someone addressed him.

If the duke had business in London, he would take his carriage to Worksop where he had it loaded onto a railway wagon. Upon his arrival at his London residence, Harcourt House in Cavendish Square, all the household staff were ordered to keep out of sight as he hurried into his study through the front hall.

He insisted on a chicken roasting at all hours of the day and the servants brought him his food on heated trucks that ran on rails through the tunnels.

However, he appears to have had some romantic interest in other people, as he had rumoured illegitimate children and proposed to opera singer Adelaide Kemble in his youth (she turned him down).

He poured most of his time into construction projects, including extensive below-ground rooms and tunnels.

A tunnel, more than one thousand yards in length, led from the house to the riding school. It was wide enough for several people to walk side by side. Parallel to it was another, more roughly constructed and used by workmen. A longer, more elaborate tunnel, one and a half miles long, intended as a carriage drive broad enough for two carriages to pass, led towards Worksop. This tunnel was abandoned in the late 19th century when a section forming part of the lake dam failed. Remaining stretches of tunnel survive on either side of the lake. The tunnel's skylights can be seen from the Robin Hood Way footpath which follows its course and a masonry entrance can be seen between two lodges at the northeastern limit of the park.

The 5th Duke excavated to create a number of extensions to the mansion. Although cited as being "underground rooms", these apartments are strictly "below ground", as they are not covered by earth or lawn; their flat roofs and skylights are visible in aerial photographs, although at ground level they are concealed from most directions by shrubbery. The largest is a great hall, 160 feet (49 m) long and 63 feet (19 m) wide intended as a chapel but used as a picture gallery and occasionally as a ballroom. There is a suite of five adjacent rooms constructed to house the duke's library.

The underground chambers—all of which were painted pink—included a great hall 160 ft (49 m) long and 63 ft (19 m) wide, which was originally intended as a chapel, but which was instead used as a picture gallery and occasionally as a ballroom. The ballroom reportedly had a hydraulic lift that could carry 20 guests from the surface and a ceiling that was painted as a giant sunset. The duke never organised any dances in the ballroom.

Other subterranean rooms included a 250 ft (76 m) long library, an observatory with a large glass roof, and a vast billiards room.

Photos from an excellent and informative thread on Derelict Places, which also includes recent photos of the tunnels.

'Tunnel entrance to the south of the riding school'

'Plant corridor'

'Print of Welbeck from 1881'

Above ground, as noted in the quoted post, he kept to a few chambers painted pink and furnished only by commodes.

This is the 'great hall', 'ballroom' or 'picture gallery', the largest of the underground rooms:

And again in 1986:

One of his most grandiose improvements to Welbeck Abbey was the vast ballroom 154 feet by 64 feet, entirely sunk below ground and top-lit by bull’s-eye domes, well-lit, centrally heated and not at all damp. On arrival for a ball at Welbeck, guests were conveyed down to the ballroom, still in their carriages, by hydraulic lift to a gently-graded inclined tunnel leading them to the dance-floor. However, the fifth Duke never gave a ball, and the gas-lit splendour only came into its own when the sixth Duke, a distant cousin who never met his predecessor, inherited in 1870.

Source

There's a strange footnote to this strange story -- a legal case that claimed the duke moonlighted as a tradesman and faked his own death. From Wikipedia:

In 1897, a widow, Anna Maria Druce, claimed that the duke had led a double life as her father-in-law, a London upholsterer by the name of Thomas Charles Druce, who had supposedly died in 1864. The widow claimed that the duke had faked the death of his alter ego Druce to return to a secluded aristocratic life and that therefore her son was heir to the Portland estate. Her application to have Druce's grave in Highgate Cemetery opened to show that the coffin buried in it was empty and weighted with lead was blocked by Druce's executor. The case became the subject of continuing and unsuccessful legal proceedings.[9]

When it was discovered that Druce's children by a former wife were living in Australia, Anna Maria Druce's claims were backgrounded, but she was placed in an asylum in 1903. The case was taken up by George Hollamby Druce from 1903 onwards, who set up companies to finance his legal proceedings in 1905, and in 1907 even instituted a charge of perjury against Herbert Druce, the elder son of Thomas Charles Druce by his second wife, for having sworn that he had witnessed his father's death in 1864. Herbert had been born before his parents' marriage and thus was not eligible to claim the Portland title even if his father had been the duke.

The photograph which illustrates this article is that produced by the prosecution as being of the duke, but the defence denied this and said it was of Druce. Evidence of a fake burial was given by a witness named Robert C. Caldwell of New York and others, and it was eventually agreed that Druce's grave should be opened. This was done on 30 December 1907 under the supervision of Inspector Walter Dew and Druce's body was found present and successfully identified. Caldwell's evidence was so unreliable that the prosecution disowned him during the trial, and it transpired that he had habitually appeared in court giving sensational, and false, testimony. He was found insane and died in an asylum in 1911. Several witnesses were in turn charged with perjury.

Sidenote: Archduke Franz Ferdinand nearly died in a hunting accident at Welbeck, 10 months prior to his assassination. If he had, perhaps we'd be living in a very different world today.

* First name actually William, but he went by John as every other man in his family was also named William, George Foreman style.

 

[GNC]

Tunnel 1,744ft (531m) long found connecting Mexico and USA - to be used for drug trafficking.

News story

I thought this was something they had made up for Better Call Saul, but according to the article:

"Since 1993, 90 of these types of secret passage have been discovered."

Expect a whole bunch of sinkholes opening up on the border in the future.

 

[Floyd]

When we were teenagers, we found a disused tunnel at Chatsworth House.

In the pitch black we heard loud voices up ahead; ''Man, this sucks dude!''. (American tourists had also found it).

Coal brought by horse-drawn carts from the railway station at Rowsley, (3 miles away) entered the garden above the stables and took the track that went under the Cascade and it was then stored at the 'coal hole' ready to be taken by underground railway wagons to feed the eight boilers that provided the tropical climate for the great conservatory.

 

[maximus otter]

Iran unveils underground drone base​

Iranian state television on Saturday broadcast footage of an air force base for drones under the Zagros mountain range in the west of the country.

The exact location of the base was not revealed, although the TV reporter said he travelled on a helicopter for nearly 40 minutes from the city of Kermanshah to reach it.

Iran started developing drones, or unmanned aerial vehicles (UAVs), in the 1980s during its eight-year war with Iraq.

The US and Israel accuse Iran of dispatching fleets of drones to its proxies in the Middle East, including Lebanon's Hezbollah movement, the regime of Syria's President Bashar al-Assad and Yemen's Huthi rebels.

Video aired on state television showed Iran's armed forces chief of staff General Mohammad Bagheri and army commander Abdolrahim Mousavi visiting the underground site.

"More than 100 combat, reconnaissance and attack drones belonging to the army are kept for operations in this base located in the heart of the Zagros mountains," the report said.

https://www.france24.com/en/live-news/20220528-iran-unveils-underground-drone-base

maximus otter

 

[Mythopoeika]

I think drones are going to be a game-changer in war. A great leveller.
Even poor countries will be able to have the same war capabilities as wealthy ones.
Wars of the future will only be won by clever tactics.

 

[EnolaGaia]

Meanwhile, in Silicon Valley ... San Jose police discovered an underground bunker used to store over $100,000 worth of recently stolen items.

6 arrested after SJPD uncovers underground bunker with $100K worth of stolen goods inside

A commercial burglary investigation led San Jose police patrol officers to a sophisticated underground bunker at a homeless encampment near Coyote Creek and Wool Creek Drive.

Inside, officers report finding $100,000 worth of stolen items stashed away. Photos shared by SJPD show the entryway to the elaborate underground bunker, which was built into the side of the creek bed and equipped with electricity.

In pictures posted to Twitter by SJPD, stolen items included firearms, equipment and tools. ...

Officers found the bunker at a homeless encampment during a follow up to a commercial burglary that happened on Monday.

SJPD said six people were arrested on a variety of charges.

The department tweeted the firearms and other recovered items all have been returned to their rightful owner. ...

FULL STORY: https://abc7news.com/san-jose-under...t-camp-near-coyote-creek-wool-drive/12048020/

 

[JamesWhitehead]

The Gay-Brecht hypothesis was that begging was just another business!

 

[EnolaGaia]

A beer cave (underground chamber used for cooling in the pre-refrigeration days) was recently rediscovered in Iowa.

19th century beer cave rediscovered in Winterset

... The beer cave, which is an earthen cooler, is just east of Highway 169 on property that is now a farm equipment supplier. ...

It is close to what was Madison County's first brewery.

A local business directory from 1869 shows the brewery was already in operation, though the year of its founding is uncertain.

While some locals had known about the beer cave on the edge of town, its existence had been hidden for generations.

"We were boring in these power lines underground, and they just ran into some rock," said Chuck Johnson, the electric superintendent. "They started digging it up and figured they hit a rock shelf." ...

"When we poked our head in and saw the arched ceiling — there isn't a flaw in it," Johnson said. "It's just like it was brand new."

For now, the cave is full of water, and local officials are waiting until fall when the water resides to take a full digital scan. ...

FULL STORY: https://www.msn.com/en-us/foodanddr...eer-cave-rediscovered-in-winterset/ar-AAZy3pv

 

[Stormkhan]

I'm forever coming across "lost" underground rooms.
In one (rented) home, it was half of an accessible cellar. Trouble was, the floor - our living room - was right above it ... and a single-layer of planks. This made heating a family room ... problematic.
In our current shop, the landlord "discovered" the cellar below it was practically flooded by sewage when an adjoining property was flooding! So ... he paid some (alledgedly) qualified firm to drain it ... then got some cowboy builders to chuck hardcore down the steps (the only access in the alley) then concrete it over. We now have a huge damp patch spreading from under shelving, access ramps etc. staining the carpet. Guess who's going to have to close when the landlord can be bothered to pay builders!
Our current place is the ground floor of a Georgian farmhouse. It's the lowest rating possible for energy efficiency, isn't connected to gas, can't have smart meters ... and the owner proudly declared when we moved in that "yeah, there's a cellar. We drained it, painted over the damp on the walls, but we've carpeted over the access hatch, so it should be okay."
Hmmmmmmmmm.

 

[MorningAngel]

I'm forever coming across "lost" underground rooms.
In one (rented) home, it was half of an accessible cellar. Trouble was, the floor - our living room - was right above it ... and a single-layer of planks. This made heating a family room ... problematic.
In our current shop, the landlord "discovered" the cellar below it was practically flooded by sewage when an adjoining property was flooding! So ... he paid some (alledgedly) qualified firm to drain it ... then got some cowboy builders to chuck hardcore down the steps (the only access in the alley) then concrete it over. We now have a huge damp patch spreading from under shelving, access ramps etc. staining the carpet. Guess who's going to have to close when the landlord can be bothered to pay builders!
Our current place is the ground floor of a Georgian farmhouse. It's the lowest rating possible for energy efficiency, isn't connected to gas, can't have smart meters ... and the owner proudly declared when we moved in that "yeah, there's a cellar. We drained it, painted over the damp on the walls, but we've carpeted over the access hatch, so it should be okay."
Hmmmmmmmmm.

Sounds like our old shop building. I work for Argos our shop closed in lockdown and never opened again, it was a big shop. We moved into Sainsburys eventually. Anyway our old shop had a culvert in the basement. Because of that there’s a pump has to be kept running. Once we moved out they don’t seem to have bothered keeping the electricity on. They just let it flood and the poor shops around have had it flooding their cellars too.

 

[escargot]

'ave we'ad this'un?

The locally famous Llandudno tunnels are being explored.
People have died, and more will.

Explorers open up 'hidden world' of eerie tunnels beneath Llandudno that lead out to sea

On a grass verge just a stone’s throw from Llandudno’s Victorian Pier arcades lies a nondescript steel manhole cover. It’s always locked. The caution is needed, if only to stop the curious venturing into a lost subterranean world that is as dangerous as it is spectacular. Youngsters have died down here.
...

For the past 37 years the Great Orme Exploration Society (GOES) has been learning more about Llandudno’s world famous copper mines, including those on the Great Orme itself. For the past six months there’s been a renewed focus on the Ty Gwyn mine, originally “discovered” by a clumsy cow near the North Shore and upon which the Victorian resort was built soon after.

 

[MorningAngel]

Ghosts of Glasgow Subway​

https://www.british-paranormal.co.uk/ghosts-of-glasgow-subway/

 

[Yithian]

Another creepy cave mystery:

http://mysteriousuniverse.org/2016/12/the-eerily-bizarre-vanishing-of-kenny-veach/

One of my favourite YouTubers has gone in search of Kenny.

There's a good write-up of this mysterious disappearance here:

================================================================

M Cave and the Unexplained Disappearance of Kenny Veach​

September – October 2019​

Desert hiker goes searching for mysterious cave, leaving more questions than answers.​

BY ERIC CACHINERO

“That aint nothing. I am a long distance hiker. One time during one of my hikes out by Nellis Air Force Base, I found a hidden cave. The entrance to the cave was shaped like a perfect capital M. I always enter every cave I find, but as I began to enter this particular cave, my whole body began to vibrate. The closer I got to the cave entrance, the worse the vibrating became. Suddenly I became very scared and high-tailed it out of there. That was one of the strangest things that ever happened to me.”

In late 2014, these words were posted to a YouTube video titled “Son of an Area 51 Technician.” The man behind the screen was Las Vegas resident and avid hiker Kenny Veach, using the screenname snakebitmgee. Unbeknownst to him at the time, his comment would set in motion a series of events that would lead to one of Nevada’s most puzzling urban legends.

Kenny’s comment sparked interest like wildfire. After posting his original comment, several YouTube users encouraged hiker Kenny to seek out the cave and enter again, this time documenting his hike, and providing evidence of his strange discovery.

He obliged.

He set off to find the mysterious cave for a second time, armed with a 9-millimeter handgun and a video camera. Upon his return, he posted a video of his discoveries. Much to the dismay of those following his claims, he was unable to locate the cave, and his video didn’t seem to reveal any clues to the mysterious M Cave he had discussed in his original comment.

His video was met with much criticism, and YouTube commenters both encouraged and provoked him to try for a third time to seek out the cave. Kenny again obliged, though one comment would stand out among all the others as an ominous foretelling.

It read, “No! Do not go back there. If you find that cave entrance, don’t go in, you won’t get out.”

On Nov. 10, 2014, Kenny set off on his last hike. He told his family he was going for a “short, overnight trip,” though he would never return.

Continues With Video:
https://nevadamagazine.com/issue/september-october-2019/11423/

 

[Mythopoeika]

On and off, I've been following the Kenny Veach saga for a while now.
He either got killed and eaten by wild animals or decided to 'disappear' himself, I think.

 

[uair01]

The door to the supposed Hamaz command center is suitably spooky. Like finding a new Great Pyramid chamber.

 

[maximus otter]

Serial killer Fred West ‘had access to network of secret underground tunnels’

Serial killer Fred West had access to a network of secret underground tunnels he could have used to carry out 12 murders.

He’s said to have had detailed knowledge of the complex 'underground world' beneath Gloucester that has been shrouded in secrecy for decades.

Urban explorers have uncovered evidence that is believed to show 22 miles of interconnected tunnels passing through many of its major sights.

The tunnels under Monk’s Retreat in Gloucester

Some of the subterranean chambers are just yards away from the so-called House of Horrors in Cromwell Street.

West is also known to have had contracts to carry out works across the city that would have given him access to the network, locals claim.

Speculation was heightened among the community in May 2021, when the Clean Plate Café on Southgate Street saw extensive excavations take place in its basement as part of an investigation into the unsolved disappearance of local girl, Mary Bastholm in January 1968. West was said to have been contracted to carry out various buildi and construction work in the basement of the café, and previous excavations at that site.

In the 1990s during the police investigation into the Wests, some blue fabric and part of a school exercise book were recovered from a hidden space behind a wall in the basement of the cafe, believed by many to have belonged to Mary.

https://www.thesun.co.uk/news/26245863/serial-killer-fred-west-secret-underground-tunnels/

maximus otter

 

[maximus otter]

Eerie car graveyard dubbed ‘Cavern of Lost Souls’ full of ditched motors



An eerie car graveyard dubbed the "Cavern of Lost Souls" is full of ditched motors left abandoned for decades.

Rotting shells of the never-ending pile of vehicles lie still in an abandoned Welsh mineshaft that resides underneath a mountain.

Located in the Ceredigion/Gwynedd area of west Wales, near a village called Corris Uchaf, this disused mine lies silent and flooded as it begins to crumble away.

It's workers are long gone and the only light that shines in this place is the single beam that makes its way through a small opening above the main cavern.

But the most notable thing about this former workplace is the remarkable stack of cars that reach the ceiling.

Despite the relative calm that engulfs this place, where all you can hear is water droplets dripping from the ceiling, it is incredibly dangerous to get to.

In order to access the cave, you are required to grapple down a 90-degree cliff, where old paths have eroded away and slippery slopes await.

But should you overcome the horror trek, then several tons of rotting iron, oils, antifreeze, and plastic that turn the water a menacing emerald green await.

https://www.thesun.co.uk/motors/26279387/eere-car-graveyard-cavern-lost-souls/

maximus otter

 

[Erinaceus]

I wonder whether any of the cars have a body inside?

 

[Stormkhan]

I imagine protective gear is a must - all that rusty, sharp-edged iron!

 

[ramonmercado]

A Jersey -Guernsey-France Tunnel.

A series of roadshows are being held to further explore linking the Channel Islands to France via an undersea tunnel.

The idea is being driven by local entrepreneur and former Guernsey Chamber of Commerce president Martyn Dorey. Mr Dorey has taken inspiration from tunnels that link the Faroe Islands and believes a Channel Islands Tunnel would bring economic benefits. Having spent the past five years on the idea, he said support for the project has now gathered. Mr Martyn cofounded the Connect 3 Million campaign, external to build the sub-seabed link in 2019, and the group has been lobbying decision-makers and politicians since.

The Faroe Islands to the north of Scotland have a population of about 53,000 and spent hundreds of millions of pounds on a subsea tunnel network.

A rail tunnel between Guernsey and France via Jersey would cost an estimated £5.6bn and take up to 10 years to build, according to the campaign group.

https://www.bbc.com/news/articles/cpw7dd78j5jo

 

[MorningAngel]

Eerie car graveyard dubbed ‘Cavern of Lost Souls’ full of ditched motors



An eerie car graveyard dubbed the "Cavern of Lost Souls" is full of ditched motors left abandoned for decades.

Rotting shells of the never-ending pile of vehicles lie still in an abandoned Welsh mineshaft that resides underneath a mountain.

Located in the Ceredigion/Gwynedd area of west Wales, near a village called Corris Uchaf, this disused mine lies silent and flooded as it begins to crumble away.

It's workers are long gone and the only light that shines in this place is the single beam that makes its way through a small opening above the main cavern.

But the most notable thing about this former workplace is the remarkable stack of cars that reach the ceiling.

Despite the relative calm that engulfs this place, where all you can hear is water droplets dripping from the ceiling, it is incredibly dangerous to get to.

In order to access the cave, you are required to grapple down a 90-degree cliff, where old paths have eroded away and slippery slopes await.

But should you overcome the horror trek, then several tons of rotting iron, oils, antifreeze, and plastic that turn the water a menacing emerald green await.

https://www.thesun.co.uk/motors/26279387/eere-car-graveyard-cavern-lost-souls/

maximus otter

Instagram fans ruining special places, says Gwynedd caver https://www.bbc.co.uk/news/uk-wales-68660455

 

[oxo66]

A Jersey -Guernsey-France Tunnel.

A series of roadshows are being held to further explore linking the Channel Islands to France via an undersea tunnel.

The idea is being driven by local entrepreneur and former Guernsey Chamber of Commerce president Martyn Dorey. Mr Dorey has taken inspiration from tunnels that link the Faroe Islands and believes a Channel Islands Tunnel would bring economic benefits. Having spent the past five years on the idea, he said support for the project has now gathered. Mr Martyn cofounded the Connect 3 Million campaign, external to build the sub-seabed link in 2019, and the group has been lobbying decision-makers and politicians since.

The Faroe Islands to the north of Scotland have a population of about 53,000 and spent hundreds of millions of pounds on a subsea tunnel network.

A rail tunnel between Guernsey and France via Jersey would cost an estimated £5.6bn and take up to 10 years to build, according to the campaign group.

https://www.bbc.com/news/articles/cpw7dd78j5jo

The excellent B1M youtube channel released a report on the Faroese tunnels just last week.

 

[Floyd]

@cycleboy2

Re: Tunnel shafts

A good article here about these shafts.

(Some pilot tunnels were less than 5' high. No thanks).

That so many construction shafts were sealed and backfilled – rather than being retained for ventilation – has left an unwelcome legacy, with records of their location often lost and the land above developed. Typically, the fill material is supported on a timber frame above the arch; if the fill becomes saturated, rotting and crushing of the timbers can follow, leading ultimately to their failure and the load’s transfer onto the lining. Of the five hidden shafts in a North Yorkshire tunnel, closed in 1958, three have given way since the Seventies. Investigations to locate such shafts continue today, their significance in liability terms not lost on duty holders.
https://www.railengineer.co.uk/tunnel-vision/