Today on "Impossible Engineering"...
The London crossrail,
Europe's biggest construction project.
The new crossrail trains
will carry 200 million passengers
in and out of London every year.
It's very exciting.
Pushing urban construction to its limits...
These machines allow you to pump 60 tons an hour.
It's quite an art to see.
...Engineers must look to the innovative pioneers
of the past...
It's amazing that they were able to build this bridge
in this torrent.
Aah!
I love the industrial revolution.
...To make the impossible possible.
-- Captions by vitac -- www.Vitac.Com
captions paid for by discovery communications
London -- one of the world's most populated megacities.
As the home of almost nine million residents,
with 31 million visitors each year,
this nearly 620-square-mile Metropolis
is grinding to a halt.
It's a problem that engineer
and commuter Camilla barrow experiences every day.
London is a fantastic place to live.
Everyone wants to be here. There's a lot going on.
However, catering for these people
in terms of transportation is critical,
and as you can see right now, it's bursting at the seams.
Every day, more than 11 million people
utilize London's vast transportation system,
including 3 1/2 million
riding the London underground alone.
The current London underground
is about 150 years old,
and it's a fantastic system and caters for a large capacity.
However, it was never anticipated
that it would cater for this amount of people.
To solve this seemingly insurmountable problem,
engineers are embarking
upon Europe's biggest construction project.
10,000 workers spread
across 40 different construction sites
are creating a brand-new rail
network straight through the capital's heart.
For operations executive Michael Bryant,
this project poses a series of complex challenge.
Underneath London is a veritable labyrinth
of tunnels for all sorts of purposes.
It's extremely complex.
Lots of the buildings there,
particularly the large buildings, like the shard,
have piles that go down 20,
30, or even 40 meters down into the chalk level,
so it really is like threading a needle.
Stretching 73 miles,
the network will pass through 40 stations.
The system features an astonishing 26 miles
of freshly dug tunnels,
intricately woven through the existing underground
rail system, and deep building foundations
of this complex subterrane world.
In 2012, eight gigantic 1,100-ton tunnel-boring machines
operating 24 hours a day, 7 days a week
begin creating this new network.
Right now, crossrail is a megaproject.
It's very complex.
It's costing approximately £15 billion.
It's probably the type of challenge
that a civil engineer
would dream of through most of his or her career.
Not only do engineers have to find room
for 26 miles of new tunnels.
They must also create space for 10 new stations,
including one serving the financial district,
canary wharf.
All of the land is full, as you can see up there,
so the only place to do it was in the water.
The challenge was to deliver a concrete box
28 meters below water level.
The option of failure just did not exist.
So how do you create a train station
deep inside the river Thames?
To accomplish the impossible, engineers must look
to the greatest innovators of the past.
Traveling along Rome's river Tiber,
professor Rhys Morgan
is in search of an ancient structure
that has withstood the power of mother nature for millennia.
Oh, wow!
It's amazing that they were able to build this bridge
thousands of years ago in this torrent.
Oh!
Aah! Aah!
Oh!
Constructed in 62 B.C.,
the Pons Fabricius is the oldest Roman bridge
still standing.
That's a real strong current there.
The foundations must be extraordinary
to deal with that river.
This bridge has endured it all --
wars, earthquakes, floods, and countless numbers of people,
horses, and carriages.
But the foundations of the bridge still endure.
The Roman curator of roads
Lucius Fabricius commissioned the bridge.
The very core of the bridge,
the foundation in the center,
is where the clever bit happened almost 2,000 years ago.
The Roman engineers had to come up
with a revolutionary method of building
while the water was in full flow.
What they designed was ingenious.
It's known as a cofferdam.
The cofferdam first required
a ring of timber piles
that were bound together and driven into the riverbed.
A second, larger-diameter pile posts
was then added to encircle the first.
The gaps between the piles would be filled with Clay
to waterproof the central enclosure.
So they had to pack the Clay
all around really densely.
And then, when they were happy,
they would remove the water from inside the inner ring.
Look at that. It's really working.
And now I'm down to the riverbed.
When all the water was removed from the inner ring,
the builders could start working on the foundations.
I'm going to use this stick as the central pier.
And there you go. Fantastic.
Once the foundations were built and the pier
could be put in place,
the cofferdam could be removed,
and the rest of the bridge could be built around it.
And there we are, Roman engineering at its best.
The revolutionary use of a cofferdam
at the Pons Fabricius means this over-200-foot bridge
still stands as a testament to Roman innovation.
When it came to building solid structures
in the water, Roman engineers
really did make the impossible possible.
The engineering team at canary wharf
are taking the groundbreaking cofferdam
and implementing it on a gigantic scale.
They drive nearly 1,400-foot-long tubular
steel pipes into the dock floor
to create a cofferdam big enough
to hold the new 820-foot-long station.
But this behemoth construction project
could pose major problems for the high-rent neighbors.
The traditional method of creating a cofferdam
is actually to hammer steel members into the ground.
And as you can imagine, that makes a lot of noise,
a lot of vibration, creates a lot of dust --
major disruption.
So we had to come up with something that was better.
To overcome this hurdle,
engineers utilize a new technique
called silent piling.
Rather than hammering the piles, a state-of-the-art machine,
called a giken, does the work.
Weighted to the dock bed and using powerful hydraulics,
it silently twists
and pushes the first three piles into the ground.
The machine then crawls
across and secures itself to those piles,
using them as anchors, before pushing in the next one.
This process is repeated
until the cofferdam wall is complete.
We went for the first three years of the project
without a single complaint from any of the neighbors.
Once the cofferdam walls are in place,
engineers can begin the mammoth task
of removing the water.
We progressively took out 98 million cubic meters
of water from the cofferdam,
and that's equivalent to 40 Olympic swimming pools.
336,000 tons of material are then excavated
until finally engineers reach a solid foundation
60 feet below, from which to begin construction.
So we have four floors below water,
a floor at water level that we call promenade,
and then there's two floors above and the roof garden.
At maximum capacity, 24 trains an hour
will carry a staggering 68,000 passengers
a day across the network faster than ever before.
But creating this station
is only a fraction of this megaproject,
and to complete the roving underground system,
engineers must look to innovations of the past...
French explorers have left here to travel the globe.
...To make this impossible rail system possible.
Deep below the streets of London,
the biggest construction project in Europe is underway.
A complicated new rail system with 26 miles of tunnels
and 10 new stations is unfurling.
It's a fantastic project.
You're working with some of the top, top expertise
in the industry.
It's very exciting.
But creating a colossal new railway above
and below one of the planet's
most densely packed cities raises
significant engineering challenges.
The most obvious issue is working around
this massive infrastructure that's already in place.
We've got people living here, people working here.
To carve out a 130-foot-deep
labyrinth of tunnels beneath the city,
eight 10-million-pound mega boring machines
are required.
These monsters are 23 feet in diameter
and as long as 14 double-Decker buses.
Project manager Jules Boyd
must make sure London's infrastructure
and residents remain intact.
One of the constraints on the crossrail operation,
which is a massive operation,
is to virtually pass by unnoticed to our neighbors.
When the tunnels are dug,
problems can occur
as the surrounding earth resettles,
causing cavities, or settlement troughs,
to appear.
If the settlement trough increases,
a building's foundations could shift,
causing structural damage.
This is a real historical center of London,
and it has to be protected.
So how can engineers
keep these ancient buildings safe?
It's a challenge that would require some inspiration
from the great innovators of the past.
Tunneling under cities isn't new.
In the 6th century B.C.,
to have a supply of fresh water
that couldn't be cut off by enemies,
the residents of the Greek city Samos dug underground aqueducts.
They must be getting thirsty by now.
Cheers!
Whoo!
The soft volcanic rock beneath Naples
meant huge networks could be dug for businesses,
churches, and even a theater, where emperor Nero
is said to have performed.
Ooh, he's on fire tonight.
Limestone mining under Paris created tunnels
for what would become the world-famous catacombs,
where the bones of six million former
inhabitants now reside.
- Uh-oh.
Hold on. Push.
But any city excavation comes with a risk.
Ah, that is better.
To unearth one of the greatest engineering breakthroughs,
Dr. Rhys Morgan is exploring
the northern coast of France.
Here at the historic Dieppe harbor once stood a massive
lock called a sluice gate.
This large sluice gate would have opened,
allowing the ships to come in and out of the harbor.
The gate had been constructed
to stop the buildup of silt
and pebble deposits and was a vital tool
in keeping the harbor entrance clear.
It was around about the end of the 18th century
that the sluice gate stopped working,
and this had a real impact on the economy.
The gate's foundations no longer held their weight,
and in 1802, French civil engineer
Charles Berigny had an inspired idea.
So this is my demonstration of the sluice gate
and the problem that was happening underneath.
First of all, we had the rocks
on the bottom of the seabed.
On top of the rock was a softer top layer,
and it was on top of this softer
top layer that the foundations of the sluice gate sat.
Now, the problem was that the water
coming in through the harbor
was going underneath the foundations of the sluice gate,
and it started washing away
and eroding the softer particles of the top layer,
and that meant that the foundations
of the sluice gate would be destabilized.
Berigny's solution to the problem was brilliant.
First of all, Berigny drilled
a series of holes five foot deep
through the foundations of the sluice gate,
down into the soil where it eroded away.
And then this was the really ingenious bit.
He got a piston pump, what he called a blow pump,
and he filled that with Clay grout.
And with a series of hammer blows,
he forced the cement down into the soil below.
The cement's pouring through the holes,
filling up this subsoil below
and making those foundations nice and stable.
As Berigny's Clay grout was hammered
through the predrilled holes,
it spread out beneath the masonry foundations,
squeezing into and filling the gaps
created by the erosion.
After a period of time, the grout set hard.
Okay. We've left it awhile.
We're gonna see how it set.
Because it's solidified, it just stays in place,
and that would have really helped the foundations
of the sluice gate.
Berigny's work was a resounding success.
This was the very first example,
from Charles Berigny, of injection grouting,
and it's used in civil engineering projects
all over the world today.
Fantastic.
But adapting this engineering
breakthrough to support an entire city
is on an altogether different plane of difficulty.
To keep London from falling down,
the crossrail team must once again
make the impossible possible.
In London, engineers are working
on the largest construction project in Europe --
the crossrail.
But keeping the city
standing above this sprawling network
of hollow tunnels relies
on an early-19th-century breakthrough --
injection grouting.
Taking Charles Berigny's revolutionary
engineering one giant leap further,
the crossrail team are advancing these injection techniques
to create one of the most sophisticated
stabilizing systems on the planet.
Up on the corner of this building,
there is one of the many a.T.S.Es.
There's another one up here, and you'll see targets.
These are essentially prisms.
High-tech surveying instruments
known as automatic theodolite systems,
or a.T.S.Es, are placed strategically across the city.
The a.T.S. Fires a beam of light at its reciprocal prism.
Engineers use specialized computer software
to continuously measure the angle of the beam.
If the angle changes too much,
this can indicate a shift in the foundations.
If any of these points starts moving,
then the grouting program can be tuned
to actually compensate for any settlement.
Underground, the team is reacting to new information
from the aboveground a.T.S.Es.
At 10-foot intervals along the length
of the grouting tunnel are a series of injection
pipes that fan out above the tunneling work
and below the delicate buildings.
Principal engineer cliff kettle is
getting the grout to its final destination.
So grout comes via the injection line
from the piloted pump,
will come up this bore hole,
will isolate the individual sleeve.
This rubber sleeve will push open.
The grout will exit here, at a fracture in the ground,
and it will go into the ground.
As the injection rods are pushed into position,
over six gallons of grout at a time
are forced out through the rods
and into the fissures of the ground,
ultimately leveling the foundations
and lifting the buildings back into place.
Some of the facades of these buildings here are 70,000 tons.
We see on a daily basis that just the injection
of maybe three or four cubic meters
of grout can move that building several millimeters.
Spanning five years,
it's the biggest compensation project
the world has ever seen.
Compensation grouting is absolutely vital for the project
because it does something that there
is no other process for.
There are many locations across crossrail
where the excavation couldn't have been completed
without the protection provided by compensation grouting.
Excavating tunnels safely is one thing,
but converting them into a high-tech rail network
is a greater challenge.
To accomplish this monumental task,
project manager Jules Boyd
is excavating these sprawling tunnels
with massive tunnel-boring machines.
The TBM's obviously a big machine.
It's the factory that builds segments of one size.
It's building very fast.
As TBMs dig,
they automatically line the freshly exposed Clay
with prefabricated concrete slabs,
quickly shoring up and sealing the walls.
But when they arrive at a future station site,
these engineering behemoths hit their limits.
It's not very flexible in terms of size.
It will build one size tunnel only,
which is what it's made it do.
And to sculpt more complex, cathedral-like stations,
engineers must address a serious problem.
If the freshly exposed Clay is left unlined for too long,
the unstable walls could collapse.
To prevent disaster, engineers must work fast
and draw from the pioneers of the past.
The techniques that are used here
eventually led to an innovation
that would really have a huge impact
on the engineering world.
Make the impossible possible.
Engineers in London
are doing the seemingly impossible,
creating a new rail system both over
and under the city's congested core,
but to accomplish this impossible task,
the crossrail team must draw on the work
of an unlikely innovator.
At the famed natural history field museum in Chicago,
science administrator Mark Alvey
is discovering how one man's passion for preservation
helped create a revolutionary engineering tool.
These are the field museum's famous
fighting bull elephants.
They were mounted over 100 years ago,
and they're still one of our most iconic exhibits.
Created by explorer and the so-called father
of modern taxidermy Carl Akeley,
they mark a milestone in natural history display.
Carl Akeley was the museum's chief
taxidermist from 1896 to 1909,
and he experimented with various sculpting
techniques involving Clay and plaster.
His techniques were really revolutionary.
Not only did Akeley
want to display the animals in lifelike detail,
but their surrounding environment, too.
And the techniques that he used
in creating artificial rocks,
like the ones you see here,
eventually led to an innovation
that would really have a huge impact
on the engineering world.
During his search for lifelike perfection,
Akeley developed a new way of covering fake rocks
with plaster of Paris.
And you can see that
if we were to try to paint it by hand,
it'd be very tiring
and end up with very uneven results.
Now, if I use my gun here,
you can see you get a much more even consistency.
It goes on faster.
You can cover your surface much more quickly.
Previously housed in a different building,
the museum's director asked if Akeley
could make something on a bigger scale
to fix the museum's crumbling walls,
so Akeley came up with a game-changing solution.
He devised a way of shooting dry plaster through one hose
that would meet a jet of water
under great pressure in another,
mixing at the nozzle.
With this, Akeley created the world's first cement gun,
and he went on to plaster the exterior of the museum.
The cement gun was soon modified,
improved, and adapted
for all kinds of industry
and to create animal enclosures in zoos.
What Akeley achieved would be a template
for all modern cement guns across the world,
emphatically transforming the construction industry.
It's been used for anything
from bespoke architecture...
To pool lining...
And even cliff stabilization.
Carl Akeley was a real pioneer.
His contributions to the world
of engineering are truly remarkable.
At crossrail, a premixed wet concrete known
as shotcrete is pumped through a specially adapted,
supersized, and automated version of Akeley's machine.
At the nozzle end, high-pressure air
is used to accelerate the mix towards its target.
Historically, people used to spray by hand.
These machines allow you to pump up
to maybe 60 tons an hour.
This sophisticated fast-curing
mix of shotcrete stabilizes the walls
and forms the permanent tunnel lining.
This is the shotcrete.
It's essentially a concrete mix with small aggregate.
It's got these things,
which are like small high-tensile steel fibers.
They're like reinforcing bar, effectively, on a micro scale.
I've worked on quite a lot of tunnels.
This is exciting.
There's a lot going on,
and we're changing the culture
to one that is infinitely more safe
than it has been historically.
With a staggering 26 miles
of brand-new tunnels now constructed,
the momentous task of creating
a high-tech railway is in progress.
We're now in our tunnel fit-out phase.
We're putting in our ventilation,
all our high-voltage power and signaling.
And it's starting to look like how it'll look
when trains will run through it.
And the biggest and most challenging job
is laying the tracks.
On our project, we have four different types of track.
There's approximately 108 meters is each section,
and you've got about 47 kilometers
of this across the project.
But just how do you install this many miles
of rail through an elaborate tunnel system?
To do this, engineers must look to the past...
What incredible feats of engineering.
I love the industrial revolution.
...To make the impossible possible.
The London crossrail is Europe's largest
construction project,
extending the city's existing underground transit system
by an impressive 26 miles.
But to install so many miles of new track,
modern engineers must look to breakthroughs from the past.
What incredible feats of engineering.
I love the industrial revolution.
Architectural historian Jen Masengarb
is in California
discovering the secrets behind one of America's
most audacious construction projects.
In the early 1800s,
it would have taken more than six months
to cross the continent by horse.
But all that changed on July 1, 1862.
The signing of the pacific railway act
by Abraham Lincoln
authorized two companies to build an 1,800-mile-long railway
between California and Nebraska.
And the two railroad companies had an incentive to move fast
because they were paid by the mile --
$32,000 per mile.
And so they were off, union pacific
starting in the east and moving west, central pacific
starting in the west and moving east,
racing across the continent to each other.
Despite the challenging terrain,
union pacific workers
were soon laying an astonishing 4.2 miles
of track a day.
Key to their staggering progress
was a method devised by two brothers,
Jack and Dan casement.
The casements' method involved creating
an entire moving city.
Locomotives pulled sleeping berths,
dining cars, and kitchens,
providing everything for thousands of workers.
This might look like just a simple cart,
but it's got a couple really cool features.
Each cart had these two iron bars
along the front and the back,
which made it possible for the iron rails
to slide to the edge.
And then these rollers
positioned the rail right into place,
so it could be slid right down on the ties.
It saved valuable seconds,
and all those seconds added up along
the project really made a difference.
For the ingenious cart to be effective,
the workers split into two teams.
The first team used a horse and wagon
to deliver the railway ties to the front of the line,
laying them in place with a pair of tongs.
At the same time, another crew would be
in the back, lifting the rails into position on this cart.
Two men at the front of each rail,
two men at the back.
And then this cart would be pushed to the front of the line.
Wheel out.
As the cart moved into position,
it was the responsibility of two workers
at the front to grab the rail
with their tongs and pull it off the cart
and then two workers in the back
to align the two rails.
The foreman would yell "good iron,"
and the cart would move forward.
-Good iron. -More here.
Behind the cart, other men, called strappers,
spliced the rails together at the joints.
Behind the strappers,
spikers secured the rails to the wooden ties with spikes.
And then more carts came from behind
with more materials to lay.
Hearing of union pacific's success,
central pacific also adopted this swift technique.
The casement method revolutionized track laying,
and by may 10, 1869,
just five years after work had started,
the two construction crews met,
and a golden spike was planted
to mark this American engineering triumph --
the transcontinental railway.
At crossrail, the engineers are taking the casement method
and giving it a 21st-century upgrade.
Behind me is the multipurpose gantry,
and really, mpg is a real-life transformer.
We have four of them on this project
that were designed for crossrail.
These modern-day,
million-dollar casement trolley cars
drag 350-long sections of steel rail into position
and place them on both sides of the tunnel floor.
You've got approximately 47 kilometers along routed rail,
so a large amount of track we need
to install, all through utilization of the mpg.
Next, the ties, or sleepers,
are positioned in between the rail sections.
This mpg can lift up 28 sleepers
in one go and position them
in exactly the correct location.
Across this project,
we have about 70,000 sleepers we're trying to lay.
Finally, this versatile machine lifts
the rail onto the ties,
and concrete is poured to secure the railway into position.
The mpg is a real solution to address the complexities
and the magnitude of the task
we have working in this environment.
But building an intricate and massive rail network
like crossrail is one thing.
Ensuring the safety of the 200 million yearly passengers
is a different story.
To accomplish this,
engineers must look to a novel innovation
from the past...
This is the world-famous Coney Island,
a place that's provided entertainment and thrills
for over 100 years.
...To produce more impossible engineering.
Crossrail -- Europe's largest
infrastructure project.
This massive construction
is gearing up to completely change the face of travel
for millions across London.
This $18 billion network
is in the final stages of construction.
The new crossrail trains will carry 200 million passengers
in and out of London every year.
But how will engineers transport
an extra 200 million passengers
safely from street level
to stations as much as 130 feet below ground?
To address this challenge,
they look to the uplifting work
of an innovator of the past.
Mechanical engineer Michael Tobias is exploring
a thrill-seeker's paradise in Brooklyn, New York,
in search of the unlikely origins
of an everyday piece of engineering.
This is the world-famous Coney Island,
a place that's provided entertainment
and thrills to new yorkers for over 100 years.
Up until the 1930s,
this iconic attraction was the largest in the U.S.
Incredible.
But in 1891, here at Coney Island,
American inventor Jesse Wilford Reno
pioneered an altogether different type of ride.
Reno's invention was a prototype
of the world's first working escalator.
And it caused a sensation.
Named the inclined elevator,
Reno's ascending movable walkway
reportedly carried 75,000 people
in just the first few weeks.
Reno's design was a sloped walkway,
very similar to how a conveyer belt works.
There's two gears, at the top and the bottom,
a motor on the top pulling the walkway up,
down, and over again.
With its steep incline of 25 degrees
and a 7-foot rise,
Reno attached strips of wood,
or cleats, to the treads to provide traction.
And most ingenious of all, at the end of the ascent,
the cleats disappeared through a reciprocal set of cone-like
prongs that safely lifted the passengers' feet off
the disappearing treads,
enabling the track's continuous motion.
Reno's invention was soon
installed in New York's transport system.
And elsewhere in New York,
other engineers were also working
on their own escalator designs.
It was here at Macy's flagship store
where Elisha Otis, inventor of the elevator,
installed one of his earliest escalators.
But Otis' plans incorporated steps.
And by combining them with Reno's cleat and comb design,
the escalator made
for a smooth ride and safe exit.
Installed in 1927, these are thought
to be the world's last-remaining wooden
step escalators anywhere in the world.
Each step in the escalator has two sets of wheels,
which roll along two separate tracks.
The upper set are pulled by the rotating chains
while the other sets simply follow behind.
The tracks are spaced apart
so that each step will always remain level.
At the top and bottom of the escalator,
the tracks level off to a horizontal position,
flattening the stairway.
These escalators stand as a testament
to the engineering brilliance
of the men involved and form the blueprint
for all modern escalators.
Back in London, engineers are
installing a whopping 81 escalators.
But to fit so many,
some over 200 feet in length
and weighing almost 50 tons,
project manager Jules Boyd and his team of engineers
must create their own engineering firsts.
Here, you see, this is the escalator
that all of the passengers
that will use Whitechapel station
will come down this,
and it's actually very steep, as you can see.
Hanging from the rails embedded into the tunnel roof,
this specially adapted machine
excavates this vast cavern,
but instead of digging from the top down
in the usual way,
limited access from the street
means the spider-like machine
must claw its way upwards.
This is quite unique.
This is the first escalator
where the tunnel was done uphill.
I'm not aware of that ever being done
anywhere in this country before.
It's very difficult to do
because everything is at 30 degrees.
It's quite an art to see.
Because of the dedication
of those building them, the 8,200 feet of new escalators
will deliver 200 million passengers
each year to the platforms below.
The unprecedented and ambitious crossrail project
is rewriting the rules of underground construction.
When you look at it now, it's amazing to think that,
in a couple of years' time, this will be open,
the Elizabeth line.
It'll be up and running and operational.
With over 100 million working hours
already completed,
the largest construction project in Europe
is a testament to the inspirational innovations
of the past...
...and the ingenuity of those building it today.
To see the whole process from start
to finish has just been remarkable.
I mean, I'm getting towards the end of my career.
I doubt I'll do another one of these,
but you never know.
Opening in 2018, the enormously complex
and groundbreaking crossrail remains
on track and is succeeding in making the impossible possible.
If you think of all the thousands of people
that worked on this project,
the billions of pounds that were spent constructing it,
the challenges we've managed to overcome,
I think it'll be a fantastic achievement.
It's a real feat for the U.K. Rail industry.