Original subtitles

Narrator: In central europe,

This elite team of engineers

Is embarking on an epic endeavor.

You're going where no one has ever been before.

♪

Narrator: They are attempting to build

The longest underground railway in the world,

Running right through the heart

Of the mighty alps mountain range.

That's it! No, no, no! [ speaks indistinctly ]

Narrator: To construct this colossus,

The team must battle intense heat...

...Massive machines,

And dangerous explosives.

[ speaks foreign language ]

Narrator: This remarkable structure ranks

In a league of ambitious new engineering wonders

That are bigger, faster, taller, and more advanced

Than anything ever constructed before.

This is the inside story of the extraordinary challenge

Of building these giants.

♪

-- Captions by vitac -- www.Vitac.Com

Captions paid for by discovery communications

♪

The alps, europe's highest mountain range,

Soars nearly three miles high.

It forms a formidable natural barrier

Between Italy in the south

And the rest of europe in the north.

The main route through is this steep winding link

Called the brenner pass.

♪

The brenner pass crosses the border

Between Italy and austria.

It is one of the most crucial transport links in europe.

The link is made up of a highway

Carrying cars and heavy trucks

And a railway carrying both passengers and freight.

The railway is more than 150 years old

And winds slowly around perilously steep gradients.

♪

The highway is crammed with traffic and regularly closed

Due to its atrocious weather,

But the last 20 years,

Engineers have been working on a radical solution

For this transportation challenge.

It's called the brenner base tunnel

And is a brand-new rail link

That will carry both freight and passengers.

This will be no ordinary railway.

It will run through a network of tunnels

That cut right through

The rugged geography of the alps.

This is the network of tunnels

They must build to complete the railway.

The tunnels will carve a 34-mile direct line from innsbruck

In austria to fortezza in Italy.

They will run at depths close to 6,000 feet

Beneath the mighty alps.

Two huge 26-foot-diameter tunnels each lined

With 12-inch-thick concrete slabs

Run side by side for north and southbound trains.

Cross tunnels every 1,090 feet connect them

While the smaller service tunnel runs below.

Three cavernous underground refuges

Provide smoke-proof escape routes to safety

In case a fire breaks out.

Over 200 trains an hour will hurtle through the tunnel

At speeds of up to 155 miles per hour,

Slashing journey times through the alps by 55 minutes.

When complete, it will become the longest rail tunnel

In the world.

Digging tunnels through the heart

Of the tallest mountain range in europe

Is a formidable challenge.

It rests on the shoulders of project supervisor giorgio

To keep this massive project on track.

This is the biggest project in europe.

The challenges are very high.

We have to face a very hard rock.

It's gonna be the longest tunnel in the world,

So the skills will be pushed to the limit.

Narrator: This is how they'll do it.

The tunnel is too long to simply start at one end

And finish at the other,

So engineers will divide it up into sections.

First, they must dig three access tunnels

On each side of the alps in both austria and Italy.

These shafts get crews down to the main tunnel route

Through several different access points along the way.

From here, they create smaller exploratory tunnels

To understand the rock conditions

Surrounding the main tunnel.

Next, huge custom-built tunneling machines

Bore the majority of the two main tunnels.

Workers use explosives to excavate the cross tunnels

And emergency stops.

Digging several sections of the tunnel

At once cuts the overall build time by half

Compared to digging a long tunnel in one go,

But they have to get their measurements millimeter accurate

To make sure all the tunnel sections meet up.

[ explosion ]

[ cheering ]

Narrator: Excavation began in 2007.

It took workers over 10 years just to prepare the site

And dig the smaller preliminary tunnels

Down to the main tunnel route,

And that was the easy part.

Now the project enters its most ambitious stage.

On the austrian side, engineers are gearing up

To excavate the exploratory tunnels

South towards the border.

Meanwhile, in Italy, they're getting ready to start

Digging the two main railway tunnels.

To construct the subterranean passages,

Workers have had to dig out two huge caverns deep underground.

♪

These will house a pair of mountain-eating monsters,

Two huge tunnel boring machines, called tbms,

That will excavate the rock.

Project lead giorgio's first challenge

Is to transport the pieces of these colossal machines

From the factory where they're being fabricated in germany

To his underground labyrinth in Italy

Where they will be assembled.

I am supposed to know this place like the back of my hand.

Problem is that logistics

And everything change on a daily basis,

So you know it like the back of your hand,

But it's a different hand every day. [ chuckles ]

Narrator: Each tunnel boring machine is 656 feet long,

Weighs a colossal 3,031 tons

And is powered by a huge

5,700-horsepower engine.

At the front of each machine, a massive 35-foot-wide cutter

Head claws through the rock.

Behind, a thick metal skin shields a conveyor belt

That clears the debris.

Further back, huge hydraulic pistons

Grip the rock side walls

And drive the cutting head forward with a force of 35 tons.

Boring stops only to reposition the grippers every 5 1/2 feet.

Finally, a robotic arm installs concrete segments

To seal the tunnel and form its walls.

[ machine whirring ]

These digging demons can punch through up

To 100 feet of solid rock every single day.

♪

It's winter time and peak tourist season in the alps.

♪

3,000 feet below,

Giorgio's work site is overcrowded.

We have right now about 700 workers on the job,

And each one is doing a job,

But it's only teamwork that pays off,

And you'll get mad at everyone,

But you're going to need everyone.

[ speaking foreign language ]

These people have a problem with geometry,

Which is not the best thing down here.

Narrator: The tunnel boring machines

Are too big to transport

From germany to giorgio's site in one piece,

So engineers must ship them in half a million smaller pieces.

For each machine, reassembling all the pieces on site

Takes giorgio's team four months.

Positioning the cutter head at the front of the machine

Is the hardest part.

These are the cutters that penetrate the rock.

The cutter head rotates.

Usually normal condition,

It'll go three or four rounds per minute.

So you're running 7 days a week, 24 hours a day,

And this machine that is noisy, vibrates,

It sort of becomes of a life companion

For the length of the excavation.

Narrator: Lifting up the 206-ton cutting head to its final

Upright position is no simple task.

It needs to fit into a special supporting bearing

Perfectly without damaging the intricate cutting mechanism.

In charge of the megaton lift is supervisor rui.

So...

Narrator: A broken cutter head

Would set the team back by months

And millions of dollars.

Failure isn't an option.

♪

♪

Narrator: High in the italian alps,

A team of engineers

Is building the longest railway tunnel in the world.

Over the last four weeks, they've been painstakingly

Constructing one of two huge tunnel boring machines.

Today, supervisor rui and his team of engineers

Are lifting the 206-ton cutting head into place.

The team's first job is to attach the head

To two giant cranes

And slowly start lifting it to a vertical position.

Workers must constantly move the crane forward

To keep it directly above the head.

If they get it wrong,

The massive disk could swing uncontrollably.

♪

It takes four hours of meticulous work

To haul the head vertical.

Now rui's team must carefully pull the cutter head back

To slot it into the front of the machine.

♪

They move the head inch by inch

To line it up perfectly.

♪

Rui climbs inside the tunneling machine

To check that the head aligns properly.

Okay.

Narrator: There isn't enough space here to use power tools.

[ speaks foreign language ]

Narrator: So workers must bolt the head into position by hand.

Finally, after 36 hours of grueling work,

Rui's team safely secures the cutter head.

Teams work 24/7 for the next three months

Assembling the half a million parts

Of this mammoth digging machine.

As they complete every new section,

They push the cutter head further down the cavern

Towards the rock face.

They have named this giant rock-eating machine flavia.

It's the first of the two tunneling machines

That will attempt to eat through the 8.6 miles of rock

That stands between here and the austrian border.

Flavia costs a staggering $22 million,

But once tunneling, she'll be worth every penny.

A tbm like this is essential to the project.

A tbm can go to 30 meters a day.

With conventional excavation,

It would take us a very, very long time.

♪

It's may, and flavia is completely assembled.

♪

Today is a critical day.

Engineers are going to fire up the machine

For the very first time to start digging.

Project lead mario ensures engineers double-check

That every system is working perfectly

Before he pushes the start button.

[ speaking foreign language ]

Narrator: Time for the big decision.

Now it's okay.

Narrator: Tunneling is go.

This is the crucial moment mario and his team

Have been working towards for one year.

So...

♪

Narrator: The machine spins into action

And begins to burrow through the solid mountain rock.

With the machine finally digging forward,

Lead engineer giac and his team face the next big challenge.

[ speaking foreign language ]

Narrator: They must install the huge concrete rings

That will form the new tunnel walls

Directly behind the cutter head.

♪

As the machine grinds its way through the alps,

It leaves bare granite walls behind it.

There's a risk that any loose rock could fall

And crush machinery.

The concrete rings, called tubbing,

Are designed to prevent this,

But installing these heavy unwieldy slabs of concrete

Precisely is a huge engineering challenge.

This is how they plan to do it.

♪

First, workers use a robotic arm

To slide the four-ton sections of tubbing into place.

Each piece contains two thick waterproof membranes

And is strong enough to protect against rock falls.

♪

The sections sit inside

The boring machine's metal shield.

♪

Once the ring is complete, the shield moves forward,

And the workers pump fine gravel

Between the tubbing and the rock.

This helps water drain down and out at the base.

♪

Finally, they install power,

Signal systems, and rails.

The end result --

A superstrong, watertight railway tunnel

That should last for 200 years.

Narrator: Giac and his team must lay

The first set of rings perfectly

Because getting this step wrong

Could cause serious structural problems for the whole tunnel.

♪

♪

Narrator: On the italian side of the brenner base tunnel,

Main engineer giac and his team

Are installing a crucial section of tubbing.

Workers use a remote-control unit

To carefully lift each piece of concrete tubbing.

Precision here is key.

[ speaking foreign language ]

Once a piece of tubbing is in place, they cannot remove it.

This is high-pressure, highly skilled work.

As they work their way around the ring,

They must constantly check that they align each piece properly.

No, no, no, no, no! [ speaks foreign language ]

Narrator: It takes just 10 minutes to lock

All seven sections of each ring into place.

The last piece is critical.

Only if the key fits will they know for sure

That they have built this ring correctly...

Man: [ speaks foreign language ]

Narrator: ...And can continue to tunnel forward.

[ speaking foreign language ]

Narrator: One ring down, 7,999 to go.

It's a relentless battle for giac's team

To supply enough tubbing to build the rings

As the tunneling machine forges forward.

If we don't have a ring ready and installed for the tbm

To advance and get ready for the next excavation,

There's no way of advancing, so the supply line is critical.

Narrator: Engineers have come up with an ingenious solution

To keeping this machine fed with tubbing.

They make the tubbing from the excavated rock itself.

The digging machines excavate around 2,000 tons

Of debris every day.

A series of conveyor belts transports

The 8.6 miles out of the tunnel

To this custom-built factory.

Here workers recycle the rock

And transform it into the ring segments.

♪

Carlo is the head of the 190-strong

Tubbing-factory team.

They mix broken rock from the tunnels with sand and cement

To give a superstrong blend of concrete.

Next, they pour the mix into precision-built molds

And leave it to set at 113 degrees fahrenheit.

To keep up with demand, carlo has to produce

42 pieces of tubbing every single day.

A train transports the completed pieces of tubbing 8.6 miles

Down to giac's team at the tunnel face.

[ speaking foreign language ]

Narrator: The journey gets longer

As the tunnel grows deeper into the alps,

And because they move so slowly,

Trains must leave every single hour,

24 hours a day, 7 days a week

To keep pace with the digging machines.

Once the tubbing arrives,

Giac's team races to fit in place in the tunnel wall.

♪

Each piece of tubbing should hold firm

For the next 200 years.

♪

At the opposite end of the railway tunnel in austria,

Engineers are tackling a very different challenge.

One of the biggest problems tunnel engineers face

Is determining what rock lies directly ahead

Of the tunneling machine.

When you are dealing with a base tunnel,

You're dealing with some degree of unknown geology.

It is vital to have a pilot tunnel.

Narrator: The bigger digging machines,

Such as flavia,

Follow a smaller 16-foot-wide exploratory tunnel

That runs underneath and in between the two main tunnels.

The italian-bound exploratory tunnel

Is 13 miles into its 18-mile journey.

It's being drilled by this special digging machine

That is open rather than closed.

This allows the team to see and inspect the bare rock.

Our tbm is pretty much naked, you know?

You can see all the parts.

Narrator: Being exposed to the bare rock

Means it's tough work for foreman babyuk

And his team of specialists.

[ wrench thuds ]

Narrator: But the team's efforts will pay off

When the main tunnels catch up.

♪

It's now early summer.

At the italian entrance to the tunnel,

The first of the two large tunnel-boring machines

Grinds steadily towards the austrian border.

Workers here are also racing to assemble

The second digging machine.

♪

But just south of the main site, a short section of tunnel

Means engineers can't use their lengthy tbms.

♪

They have no option but to use powerful explosives.

[ explosion ]

♪

♪

Narrator: In central europe,

Engineers are digging the longest railway tunnel

In the world through the alps between Italy and austria.

[ speaks foreign language ]

Narrator: On the italian side of the project,

Part of the main tunnel is too short

To justify using a huge boring machine,

So geologist stefano and his team of specialists

Have to use an alternative -- powerful explosives.

[ speaking foreign language ]

Narrator: When a section of tunnel

Is too small to use a tbm,

The team uses explosives instead.

They pack 880 pounds of dynamite

Into over 100 precision-bored holes

In the tunnel face by hand.

[ explosion ]

They detonate them in a carefully controlled pattern.

This removes the rock they want gone

While leaving the tunnel walls intact.

Finally, they spray on quick-drying concrete

To stabilize the tunnel.

By triggering up to two blasts every 24 hours,

They can dig 32 feet of new tunnel every single day.

♪

First, engineers use this huge laser-guided drilling machine

To create the holes the explosives will sit in.

♪

♪

They have to drill each hole with millimeter precision

To create the perfect blast.

If they get it wrong,

The rock won't break away from the face properly,

Exposing the team to dangerous overhangs.

Once jumbo is finished drilling the holes,

It's time to bring in the explosives.

♪

Demolition expert carmelo has been blowing things up

For a living for over 20 years.

He's responsible for the 880 pounds of dynamite

Used in today's blast.

Dealing with this much explosives

Requires nerves of steel.

♪

Carmelo and his team carefully pack the explosives

Into the holes drilled by jumbo.

♪

They will set off each charge with a millisecond delay

From the one next to it.

This should break the rock into small chunks

Rather than big unwieldy slabs.

Carmelo himself connects the fuse.

[ indistinct conversations ]

♪

Narrator: With the charges set,

The team retreats to a safe position

And waits for the final signal that they are clear to blast.

[ speaking foreign language ]

[ explosion ]

♪

Narrator: Stefano must check the condition of the rock face

Before any further blasting can be done.

He hunts for potentially dangerous cracks.

Stefano needs to get close to the freshly exposed rock face

To make his assessment.

There's a high risk of falling rock here.

All work is suspended while stefano assesses the rock face.

Stefano gives the all clear.

[ speaks foreign language ]

Narrator: Next, the team uses diggers and dump trucks

To remove the 400 tons of broken rock

And take it to be recycled into tubbing rings.

♪

It takes four hours to completely clear the tunnel.

Finally, they spray on quick-drying concrete

Called shotcrete to stabilize the tunnel walls

Until a thicker concrete wall is installed,

16 feet of new tunnel in just 16 hours.

For the blast team, it's a good day's work.

♪

12 years into this titanic tunneling mission,

The teams on both the italian and austrian sides

Are making good progress.

The two won't meet in the middle for another two years,

But making sure they line up perfectly

When they do is a huge challenge.

On a tunnel this long,

The slightest wrong turn can have huge consequences.

When you're tunneling through a mountain,

There's no external line of sight

To check you're going in the right direction.

You're tunneling in the dark.

♪

♪

Narrator: In central europe on the austrian side of the alps,

Tunnel surveyor patrick young is in charge of making sure

The exploratory tunnel stays on course.

It's a huge responsibility.

Young: The drilling machine is a jet.

The pilot is the driver, but we're the navigator.

We're telling him where to go,

Which way, left, right, up, down.

We're controlling the work,

Making sure it's all moving in the right direction.

Narrator: This is how he does it.

First, engineers use satellite gps

To map the mountain down to 1/4-inch accuracy,

Creating reference points on the surface

And precisely plotting the route of the tunnel,

But deep underground, they can't use gps.

Without knowing exactly where the tunneling machine is,

It could easily veer off course.

To solve this problem as the machine digs,

Surveyors use a series of lasers

To take super accurate measurements of the distance

And angles it has traveled,

Leading all the way to the reference points

On the surface.

From these measurements, engineers calculate

The route the tunneling machines have taken

And keep the drivers on course,

But they will only know if they've got their calculations

Right when both tunneling teams eventually meet in the middle.

Patrick and his team must constantly

Check the tunneling machine's progress as it moves forward.

♪

They work 24/7.

♪

If the tunneling machine moves without accurate measurements,

It will quickly drift off course.

Young: As a tunnel surveyor, it is quite a lot of pressure.

It's not the easiest environment to work in.

There's explosions.

There's trucks and diggers

Driving in every direction.

Narrator: Patrick has mounted laser-surveying devices

Along the length of the tunnel.

As the tunneling machine advances,

He has to shift them to keep up with it.

Young: Going to go to the very front of the machine now,

And we have to rebuild the laser.

At least once a day, maybe twice a day,

We have to come down here and scoot the laser forward.

♪

Narrator: Patrick quickly moves the laser forward

And starts his precision measurements of checks

And double-checks.

When the laser hits this target,

Plate sends the information

Back into the main cabin

Where the driver then sees

All the information that he needs.

The work we do is vital.

Without our laser, in a very quick time,

It's going to go in the wrong direction.

Narrator: After a few final checks,

Patrick confirms that the control cabin

Is receiving the correct data,

And the tunneling machine can move forward

Knowing it's on the right path.

Young: We completed everything for today.

We're perfectly on track.

Our little paper airplane means we're receiving data.

The machine is three centimeters above the tunnel axis.

That's how they want it to be.

♪

Narrator: As the tunnels burrow deeper through the mountain,

Engineers face another herculean challenge.

Once the tunnel is complete

And trains are running through here,

Engineers need to be able to rescue passengers

In an emergency.

The longer the train tunnel,

The harder the rescue mission becomes,

And this will be the longest underground railway

In the world.

When you bring passengers in a tunnel this long,

You need to think about safety,

And of course the major threat is fire.

Narrator: One of the worst tunnel fires in recent history

Occurred on the morning of March 24, 1999.

A truck catches fire at the center

Of the seven-mile-long mont blanc road tunnel.

Temperatures soar to over 1,800 degrees fahrenheit,

Destroying vehicles and the tunnel lining.

It takes firefighters almost three days

To extinguish the inferno.

The fire claims 35 lives.

Tunnel builders today have to assume the worst and plan

For any emergency.

The brenner base tunnel is going to be the longest in the world,

So if the worst happens, how can engineers keep passengers safe?

♪

♪

Narrator: 3,000 feet below the surface of the alps,

Engineers are building

The longest railway tunnel in the world.

They're working to overcome a critical challenge.

If a fire occurs inside the railway tunnel,

How do you keep passengers safe

When the nearest exit could be 18 1/2 miles away?

The overall idea is to get rid of the smoke,

To get people away from the smoke,

Which is one of the main hazards

That we have once a fire occurs in a tunnel.

Narrator: This is how they plan to do it.

Engineers are building three emergency stations,

Called refuges,

12 1/2 miles apart deep in the heart of the mountain.

If a fire breaks out on board a train,

The driver won't stop until they reach the nearest refuge.

Here an escape route leads through fireproof doors

Into cross tunnels.

These open out into a 1,500-foot central refuge tunnel.

To stop the refuge from filling up with toxic fumes,

Special ventilation fans

And ducts extract the smoke from the train.

They safely draw it away from the passengers

Through a separate channel overhead.

With the fire securely sealed in one tunnel,

Rescue workers use the second tunnel

To transport passengers from the refuge to safety.

♪

Rosella audino is part of the team

Building the italian safety station.

Rosella has to inspect and sign off all work

On the surrounding tunnels

Before they can start building the emergency station.

With this system in place,

Passengers can access the emergency station quickly

And wait in safety until a rescue train gets there.

This ingenious safety system has added $43 million per station

To the cost of the tunnel, but in a tunnel this long,

It's essential if the worst does happen.

♪

On the italian side of the alps,

The first of the two main tunneling machines

Is already 1/2 mile into its 8.6-mile journey.

♪

Now, after four months of work

Assembling the second tunneling machine,

They are gearing up to set that off, too.

It's a huge moment for project lead giorgio

And the whole team.

Today is a special day in our project.

This is the day when the last tbm

Starts to the border.

Narrator: Tunnel managers have organized a massive celebration

To launch the last tunneling machine

On its epic 8.6-mile journey.

[ speaking foreign language ]

Narrator: In a time-honored tradition,

A priest christens the tunnel-boring machine.

They will call her virginia.

It's taken the team more than 2,000 hours

To get this massive machine ready.

Finally, it's time to start virginia up

And break into the rock wall.

[ speaking foreign language ]

♪

[ cork pops ]

[ applause ]

Narrator: Now all tunneling machines are digging.

They won't stop until they break through

At the italian-austria border beneath the heart of the alps.

Everybody that has worked on the project

Takes pride in what they have done.

Narrator: This megaproject is a once-in-a-generation endeavor.

When the railway tunnel opens in 2028,

Giorgio and his team will have excavated

More than 140 miles of tunnel.

Over 200 high-speed trains a day will form a vital new artery

From the north of europe to the south,

Slashing journey times for freight and passengers.

Thanks to the longest railway tunnel in the world,

Traveling across the alps will never be the same again.

♪