Original subtitles

narrator: a pioneering team of engineers

is digging deep on something massive.

now it's showtime.

we can read you loud and clear.

they're attempting to build an innovative

$3.5 billion circular railway

right underneath the heart of an historic capital city...

starting to roll now.

with 17 brand-new stations and 39 driverless trains.

to build the biggest construction project in the city

for 400 years,

the team must battle toxic soil

and catastrophic floods --

and collapsing earth.

man: time-wise, we're right on the limit.

no, failure is not an option.

narrator: this uniquely challenging underground railway

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

♪♪

narrator: the historic city of copenhagen

lies on the east coast of denmark.

its spectacular architecture and sights

attract millions of visitors each year.

but this creates a problem for the city's population --

the capital's roads are congested.

copenhagen's 1.2 million residents

have to battle constant gridlock

that blocks major roadways.

the city does have a metro, but, built in 2002,

it was not designed to cope with today's peak demand.

so that's why, in 2011,

beneath the center of this historic city,

this team of engineers begins building

a trailblazing new underground railway.

man: it's pretty challenging and an important project

because it is supposed to get 90 percent

of the population of copenhagen.

narrator: constructed in a circle underneath the city,

the new railway, called cityringen,

will bring the majority of the population

within a 10-minute walk to a station,

doubling the metro's capacity.

the man tasked with constructing

the railway's congestion-busting tunnels

is valerio violo.

violo: the city of copenhagen is looking at us.

it is following the progress of the construction

now on a daily basis.

they really want us to finish

and to get the metro up and going,

so that's kind of a strong pressure on our shoulders.

narrator: building a project of this magnitude

directly beneath the heart of this historic capital

is no simple task.

man: there are a lot of safety challenges from underground

works that come together, provides us with a lot of risk

and hazard that you don't normally get

in the normal construction of a building, for example.

narrator: in just eight years, this is the massive railway

valerio and the copenhagen metro team must somehow build.

the plan is to construct 17 brand-new subterranean stations

that will circle the city in a ring.

each station will be unique,

built to reflect its surrounding area.

underground, at track level,

platform edge doors will separate commuters

from the 19 miles of freshly dug tunnels

that will transport commuters around the city in minutes.

39 innovative driverless trains

will run through the tunnels.

♪♪

each train will have the capacity

to shuttle 280 passengers

between stations every 90 seconds.

the new metro will be able to transport

around 70 million passengers a year when it's complete.

♪♪

man: it's going to be a big challenge

because the city itself is relatively small and congested,

so there are challenges ahead, challenges

that everybody is willing to take on onboard and face.

narrator: building the vast underground metro

in this jam-packed capital city

involves a series of key challenges.

the team needs to excavate 17 massive holes

right in the heart of the city.

inside them, they will build the sunken stations.

to connect up each station, valerio and his team

must excavate three million tons of earth

to create the two circular tunnels for the trains.

hot on the heels of the tunnelers,

a team of track layers must position,

concrete and weld together over 19 miles of rail track.

engineers must also construct and test

the fleet of 39 new driverless trains.

one of the team's greatest challenges

will be to construct a stretch of tunnels

that must pass directly underneath copenhagen's

historic central train station

while it remains open.

♪♪

the first task is to construct the tunnels.

these must be built before work

inside the stations can continue.

we have 36 months to complete the tunneling.

there is always the possibility to make a mistake in tunneling,

and we need to be focused and to maintain our concentration.

narrator: as the son of a geologist,

valerio is no stranger to the underground.

he has over 21 years' experience on mining projects

around the world,

but the cityringen tunnels pose his biggest challenge to date.

violo: i never had such a big project to manage

and such a big company to manage all by myself.

this one was a pretty challenging task.

[ foreign ]

narrator: to excavate the 19 miles of tunnels on time,

the team is using a fleet of innovative

digging vehicles called tunnel boring machines,

or tbms for short.

violo: we had four machines working at the same time

this month under copenhagen.

narrator: each tbm is 344 feet long

and is a mobile tunnel-building factory.

at the front, a giant 19-foot rotating cutter head

claws away at the earth.

the excavated material moves away from the cutter head

on a conveyor.

it is loaded into carts for a small train to tow away.

a robot arm installs precast concrete segments

to line the freshly dug tunnel tubes.

it takes six segments to make up a complete tunnel ring

4.6 feet wide.

hydraulic pistons then push the machine forward

so the excavation process can begin again.

on average, each tunnel digging machine

can install 18 rings a day as it snakes its way under the city.

tunnelers have been digging

copenhagen's tricky sea-level geology

nonstop since 2013.

the machines claw away up to 3,000 tons

of earth, sand and super-hard rock every day.

they dig out and line an average of 3.7 miles of tunnel per year,

but this is a crucial day for the tunneling team.

one of the four machines is burrowing its way north

to what will eventually become trianglen station.

now it must break through

into the half-built station structure itself

so that the tunnels and stations connect.

claudio ramazzini is in charge

of this critical part of the operation.

man: this is the breaking side of the station.

basically, as you can see here,

here we have the concrete block,

and inside of this concrete block,

we have one of our big tunnel-boring machine,

and it's about to get in the station.

♪♪

narrator: but that's easier said than done.

to prepare for the machine's breakthrough,

engineers have built a giant concrete block

at the precise point where it will enter.

the block acts as a plug to stop earth and groundwater

flowing into the station as the machine eases through.

without this block,

the pressure from the surrounding water in the ground

could cause the wall around the machine to collapse,

creating catastrophic damage,

but already this worst-case scenario is becoming a reality.

narrator: in copenhagen, engineers are busy building

the city's biggest construction project in 400 years,

the $3.5 billion cityringen metro.

at the moment, the tunnel-boring machine

is about 35 feet behind the block.

if you get closer to the wall, you can hear the noise

of the cutter head cutting the concrete.

narrator: for claudio and the team,

the stakes are high.

we have to do the breaking on time to stay on schedule,

so the teams here in trianglen station

can finish building the station.

narrator: paul evans heads down to make the final checks.

man: some of the concerns we have when the actual tbm

literally breaks through that concrete

is the possibility of debris

flying quite a distance and injuring people.

narrator: but, with the tunneling machine

now just 16 feet away from breaking through,

the team hits a problem.

[ foreign ]

groundwater starts flooding into the station

through a gap in the top of the concrete block,

threatening the entire project.

we have a problem here of water inflow,

so we had to stop the excavation.

we need to get this fixed quickly

so that we can proceed with the breakthrough operations.

we don't want delay.

narrator: groundwater is flowing through a gap

between the outer edge of the tunnel

and the platform ceiling.

unstopped, it could catastrophically flood

the tunnels.

to stem the flow, valerio's team must drill a ring of holes

through the tunnel segments.

the holes need to be at the precise points

where the tunnel meets the stations exterior wall.

then they'll inject a special type of resin

through these holes.

the resin solidifies on contact with water

and should form a watertight seal around the tunnel

to plug the leak.

♪♪

inside, the station engineers begin battling the floodwater.

♪♪

narrator: it takes a frantic few days

working around the clock

to inject the resin

and make the station watertight.

with the leak fixed, and with just over two feet to go,

the team prepares to break through,

hoping the resin plug holds.

narrator: the station team gathers

to witness the milestone.

it's an anxious time for workers.

i've been waiting for 4 years for this machine

to arrive on this side.

♪♪

okay. now i'm going to call the pilot and say to him,

"restart and break in."

finish. no more delays.

♪♪

this is the moment of the truth.

♪♪

♪♪

i'm very happy now because we are

with the tunnel boring machine.

we have done the break-in, so...

great moment.

yeah!

narrator: success --

the tunneling team breaks through

and joins up with the station crew for the first time.

[ cheering ]

but for claudio, the hard work doesn't stop here.

ramazzini: all of the pressure gone now,

just for a few hours,

and then, again, pressure

because we have to push the tunnel boring machine

on the other side of the station.

♪♪

narrator: with the tricky breakthrough behind them,

the four tbms pick up the pace.

i can set this to... fifty percent.

yes.

narrator: the machines chew through

nearly 3,000 tons of dirt and stone

every day as they burrow underneath the city.

but getting rid of all this excavated earth

is another huge challenge for valerio's team.

violo: the tbm can build a lot of rings per day.

now considering the distance,

we are doing 18 rings per day on average.

narrator: after the machine builds each ring,

the excavated earth is carried away from the cutter head

and dumped into a series of carts.

once full, a small train pulls them out to be emptied.

♪♪

any delay of getting rid of the waste

could hold up the entire project.

narrator: but copenhagen's unique geology

creates a problem.

narrator: an old industrial part of the city

has left behind a toxic legacy.

this makes the task of managing the excavated earth

even tougher.

i'm taking some samples to be sent off for lab testing.

narrator: every day, christian's team must sample

a trainload of muck for traces of contaminants,

but he can't afford to hold up tunneling.

these samples, together with the muck,

sent for analysis every day while the tbm is mining.

narrator: workers empty the dirt and rubble

from these carts into temporary pits

while they wait for the test results.

♪♪

tjustrup: every day, we get the decisions from the authorities,

and then we instruct the work site manager

how they should organize the deposit

and which muck pit is clean

and which muck pit is contaminated.

narrator: it takes 24 hours

for the result of each test to come through.

the team anxiously awaits the results.

narrator: engineers are busy tunneling

underneath the city of copenhagen

to create a massive new subway,

but they must find out if the soil is toxic.

-hi, klaus. -hi.

where is the muck going today?

is it clean? it's clean muck.

okay. thank you very much.

all the muck today is clean,

and it's going to be disposed of to the clean soil facility.

♪♪

maybe the situation is different tomorrow.

we'll have to wait and see.

narrator: each truckload of muck

travels five miles north of the city

to this unique facility.

♪♪

this is no ordinary waste dump.

workers here are using the clean coil

to extend the city out into the sea.

they're filling in an area of the waterfront

over a half square mile to create space

for a new port and park land.

tjustrup: the area is going to increase the area of copenhagen

by one percent.

the total area where we are right now

is going to be used for the public in copenhagen,

for fishing, for having picnics

and for doing some kind of playing

and whatever people like to do.

today it's a bit cold.

i'm freezing, but when the summer is coming,

maybe we can take a swim in the sea

and do some sunbathing.

♪♪

narrator: underground, the tunneling team

is still working as fast as they can.

[ foreign ]

each time the team breaks through into a station

they face the same battle,

to drag this 700-ton tunneling machine through the platform

so they can continue digging.

man: everybody wants to see the machine come in,

but then a lot of people want to see it leave again

because there's a lot of work that has to continue from there.

there are deadlines to meet.

narrator: the highly specialized tracklayers

are hot on their heels.

valerio and his team with the tunnel boring machine

are furiously chomping through virgin dirt.

our goal is to be as close as possible behind his team

so that we can all finish this project on time.

we have two tunnels, 17 stations.

we've got a deadline.

we need to achieve this fast.

narrator: paul and his team need to position the track,

secure it with concrete, and join each section together

with absolute precision.

it's no small feat.

to help them install each piece in the right spot,

they are using an innovative machine.

this rail-laying gantry crane

is fitted with precision-grabbing arms

to pick up and position the flexible pieces of rail.

man: there's a lot of skill involved in picking them up

in the right position to minimize deflection.

they do move around quite easily.

they have to because the tunnel has so many twists and turns,

it needs that flexibility.

narrator: the flexible rail helps the track layers

snake a path through the curved tunnels.

burley: with curvature in one direction,

we also come across the problem of one row

getting longer or creeping ahead of the other.

so every so often we need to perform a cut

with a quick-cut saw to make sure that we're back on

a level peg, and...

narrator: they must level up the ends of the rail

so that the next set of tracks joins up smoothly.

any bumps or misalignments could derail a train.

this is definitely, by far, the most important stage

of the track-laying process.

narrator: paul's team uses a plumb line

to help them push or pull the rails into position

with pinpoint accuracy.

burley: without these sort of accuracies,

there's a chance that the train could derail,

and i'm my head's sort of moving around like this,

i may as well catch a bus.

it needs to be smooth.

perfect.

narrator: with the tracks perfectly in place,

the team must now lock them into position with concrete.

that's easier said than done.

to secure the next 50 feet of track,

they need to pump around 20 tons of wet concrete

6 stories down to a mixer in the tunnels

and feed it to the rail crew before it sets.

it's a long distance in a short amount of time.

burley: 90 minutes is the time that we have to ensure

that the concrete is still in a condition

that we can use to lock the sleepers

into their final position.

narrator: it takes over 40 minutes

just to fill each mixer.

burley: there's an enormous amount of pressure

on these guys -- 90 minutes is not a long time.

narrator: the load reaches the concreting crew

with just minutes to spare.

♪♪

burley: time-wise, we're right on the limit.

these guys have to work quick.

time is critical.

the men in white just performing the final concrete

finishing work by hand.

narrator: for this section of tunnel,

they finished in time.

burley: today, a good day if we get 80 meters done.

only 31,500 meters to go.

♪♪

♪♪

narrator: while work on both the tunneling

and track laying picks up pace,

1,200 miles away in italy,

engineers are building the railway's

39 new driverless trains.

here, the team assembles each of the trains'

three individual carriages,

installs the doors and windows

and connects up the complex electrical systems

that will provide the driverless train controls.

once built, each train is shipped to this test facility

where davide marandola's team adds the finishing touches.

♪♪

narrator: hidden at the other end of the facility

is cityringen's high speed test track

where each driverless train must pass a series of critical tests.

today, technicians plug into train 20's computer controls

to track it's performance.

♪♪

narrator: davide will push this train to its limit.

it must accelerate and break

within a specified time and distance.

marandola: it's crucial because we need to provide a train

that is reliable.

now we are going to the test track.

narrator: if this train fails,

it could delay work on the entire fleet.

narrator: as part of copenhagen's ambitious

$3.5 billion cityringen,

engineers are testing a new fleet of driverless trains.

but for this crucial test,

a driver must sit in the hot seat.

marandola: michael, can we get the four-signal ready?

yeah.

so the acceleration is quite strong.

♪♪

okay. now you can stop.

♪♪

narrator: now for the brake test.

we are starting.

then, when we reach max speed, we make max service brake.

narrator: each train must be able to stop completely

in less than 180 feet.

marandola: okay. now you can stop.

little, yeah.

okay.

yes.

okay.

narrator: after a day on the test tracks,

it's the moment of truth.

has this train passed both tests?

marandola: we can evaluate increasing of the speed,

so this yellow line, from zero to 40.

that acceleration was 1.25,

so it has been good -- reached in good way.

narrator: the braking data shows that it stopped after

just 160 feet, under the target.

♪♪

narrator: this train heads back to the base,

having passed with flying colors.

but with 19 more trains to put through this test,

there's still a lot more work for davide's team to do.

[ beeping ]

narrator: as trains begin to line up ready to enter service,

paul's track team is working 24/7 to install the rails.

with a weld every 60 feet and over 19 miles of tunnel,

it's a relentless battle.

thousands and thousands of welds.

narrator: paul and the team plan to use an ingenious

and super fast welding technique

to stop them from falling behind.

they are preparing a fiery chemical reaction

to super heat a mixture of aluminum and iron oxide

that creates a mix of molten metal.

this liquid metal should fill the gap

between the rails in mere minutes.

♪♪

the advantage is the ability to join two unique bits of rail,

creating one seamless stretch of railway line.

now it's showtime.

narrator: the chemical reaction is instantaneous.

♪♪

the liquid metal flows from the base of the drum

into the mold.

any excess drains into these pans on either side.

burley: it's critical that we wait the right amount of time

before removing the molds.

if we remove the molds too early,

the metal will run and fall out of the joint.

if we remove it too late, we run the risk of having molten metal

stuck to the track which is very hard to remove.

narrator: once ready, they break the mold off

and leave the weld to cool overnight.

here we can see a thermite rail weld

that was completed last night.

we can see that the rail gap that we witnessed earlier

is perfectly filled with the molten metal solution.

it's had an initial grind,

and it's ready for the final grinding later tomorrow.

one rail weld completed, many thousands to go.

narrator: the super fast welding helps paul's team

join around 590 feet of track each night.

♪♪

across town, the team is gearing up to tunnel under

copenhagen's historic central station.

this iconic station was built in 1911,

and now 100,000 commuters use this crucial hub every day.

man: it's really important that we don't do any disruption

to this because this is the main hub

for central copenhagen, and all the trains heading out

to other parts of denmark,

so we cannot afford to cause any disruption

to the station at all.

narrator: for the ring of tunnels to reach

their final station, engineers need to tunnel

a mere 49 feet below this busy hub.

no tunnels have come this close

to copenhagen's oldest station before,

and digging such huge holes

so close to this historic brick-walled building,

if not done right, could cause catastrophic damage

and close this international hub for months.

pulling this off without a hitch will be a huge challenge.

narrator: in copenhagen, engineers are constructing

the cityringen metro,

but they're trying to figure out

how to tunnel underneath the city's iconic central station

without causing it to collapse.

well, where we are at the moment is right next to copenhagen's

main central station.

just beyond that fence line

is where the tbms will come through eventually,

passing under the existing rail line.

narrator: the team is so nervous about digging this section

of tunnel that they have a special crew

that monitors the operation 24/7.

it rests on the shoulders of spyros latsenere

to make sure the old station doesn't start collapsing.

narrator: the plan is for workers to excavate the tunnels

underneath the historic station.

there's a real risk that the digging could disturb the earth

around the tunnel boring machine causing the soil to shift

and triggering the buildings above ground to tilt.

to monitor for this, spyros and his team

have installed an ingenious network of lasers and prisms

all over the station to check for any ground movement.

the laser fires a beam every 30 minutes

to record the position of the prisms.

if the spot the laser beam hits suddenly changes,

this means that the prism has moved,

and the system sends an alert back to the base.

narrator: inch by inch, the tunnel boring machine

slowly snakes its way under the main station.

[ foreign ]

narrator: it's a tense time for the tunneling crew,

as they approach the point where they will make the final

breakthrough next to the main station.

okay, guys. welcome.

it's the moment they've all been working towards.

man: the main focus point today

is going to be the final breakthrough.

so of course it's not just a final breakthrough.

it's the last breakthrough of the entire project.

we've been part of this project now for the last three years,

and it all comes to this point when it breaks through.

we need to keep our focus on the safe distance

for the spectators,

and especially with this breakthrough,

there's going to be a lot of people

that want to get in there.

there will be a lot of eyes on us,

and in that respect, we want to make sure that we do this

and it's a nice clean breakthrough

and without incident. okay. thank you.

okay. thank you, sir.

narrator: but just as the tunnelers reach

the halfway point under the station,

some alarming readings alert spyros' team to a problem.

narrator: the alert couldn't have come

at a more inconvenient time.

spyros sends a team of surveyors to investigate

if the settling earth

is calling the platform's roof pillars to sink.

♪♪

we had some points moving, and we're double checking to see

if they continue to move

or if they are staying in the same level

because the tunnel boring machine

is right underneath us here,

so we'll double check if it's all right.

a lot of things could happen here.

there's a very big arch over us,

so if something happens with some of the pillars here,

if part of the tunnel starts collapsing

or something like this,

we will know it before it gets critical.

narrator: they check all 60 prisms in the station,

dodging commuters who are oblivious to the massive machine

passing right beneath their feet.

some days i can actually feel the boring machine

moving under my feet, like, vibrating the ground.

♪♪

i will transfer the calculations from today.

we can then see what was measured,

and the two points that we measured

that was close to the alarm levels

are about the same height that they were last time.

so they stopped moving down.

everything is stable,

and everything is where it's supposed to be.

narrator: the data confirms that the ground has stopped moving,

at least for now.

♪♪

so the tunnelers are clear to press on with the last

push towards the finishing line,

and the final breakthrough into the new cityringen station.

man: i think we should have them at this point here

rather than the bottom level.

in my opinion, it's a bit too close.

so we have that little bit more extra space.

narrator: hundreds of vips and officials

are due to arrive to witness this momentous event.

paul can't afford anything to go wrong.

so tomorrow everything is going to be nice and clean

and ready for the final breakthrough.

okay. i have no problems.

narrator: the team has enlisted some extra special help

to make sure the final breakthrough goes off

without a hitch.

evans: that's a statue of the santa barbara.

she's the patron saint of miners.

so wherever we go, we would like to have the statue there

as a good luck symbol for our mining,

to keep us safe wherever we may be underground.

she's brought us luck all this way,

so why shouldn't she bring us luck for the final breakthrough?

♪♪

narrator: after three years of construction work,

the day of the final tunneling breakthrough finally arrives.

everything has been leading up to this crucial event.

the final act, today is the end,

at least of the tunneling operation.

evans: we're all ready. we're all set up, ready to go.

we're just waiting for the last of the visitors

and guests to arrive,

and then we'll get the all clear,

and we'll be ready to push.

narrator: in copenhagen, engineers are coming upon

the final stages of completing the $3.5 billion cityringen.

the last major milestone is breaking down the walls

beneath the city's historic central station.

with a subterranean feast complete with champagne

and red carpet all laid out,

the pressure grows on the tunneling team.

there's a big buzz in the air,

and everyone is excited to see this happen.

welcome to the last break in of the project.

we're going to go through a couple of safety issues.

narrator: inside the tunneling machine,

sybil yensen gears up for the final push.

sybil, sybil, this is paul.

radio check, over.

hey, paul. this is sybil and tbm-4.

we can hear you loud and clear.

okay, good. everything looking good your side?

yes. we checked the pumps. everything is ready.

thank you so much.

everything is good to go on their side.

everything is how it should be.

let's go.

starting to roll now.

okay. we can start pushing now.

we'll start.

[ foreign ]

♪♪

♪♪

narrator: with one final nudge...

19 miles of cityringen tunnels are complete,

and the 17 new stations finally connect.

woo!

narrator: for valerio, paul, and the whole team,

it's the end of an extraordinary underground journey.

brilliant, fantastic, extremely happy.

for copenhagen, it means that you can walk from here

all around town

and come back from that direction.

it's the first big,

huge step towards the completion of the metro.

it's been a massive achievement for everybody involved.

everybody is so happy.

now today is just celebration.

they are just celebrating what they did.

narrator: but just one final breakthrough remains

to mark this huge achievement.

woo-hoo!

[ foreign ]

have you seen this cake?

[ cheering ]

♪♪

narrator: the last tunneling breakthrough

marks a key milestone in this ambitious

$3.5 billion project.

all the major civil engineering work is now complete.

the team has poured more than one million tons of concrete...

excavated more than 3 million tons of earth,

and installed 135,000 tunnel segments.

we've done our job, and we've done it very well.

man: it's huge. it's very big.

i really need to take time to process it.

narrator: over the coming months,

the copenhagen metro team

will continue to lay the last sections of track,

install the stations so the ticket halls can open

and prepare the 39 trains for operation.

man: when this is all finished, i want to come back

and take the first ride on the metro.

i'm definitely going to do that.

narrator: cityringen will soon ease the pressure

on copenhagen's roads

and help keep this historic capital city

running well into the next century.