Today on "Impossible engineering,"
the Shanghai Maglev... The fastest passenger train
on the planet, with a top operating speed
of 268 miles per hour.
The Maglev is faster than the formula one car.
It is flying along.
A train that defies the most basic laws of motion.
The thing that's different and very unique
about the Maglev is the fact that it floats.
It took centuries of innovation
and experimentation...
Wow, it looks like something out of the future.
To make the impossible possible.
Captions by vitac www.Vitac.Com
captions paid for by Discovery communications
China is a country on the rise.
Its largest and wealthiest city, Shanghai,
attracts people from all over the world
with its ambition.
As Shanghai's population increases,
so does its demand for space.
The city faces heavy traffic jams
and congestion on a daily basis.
Shanghai is busy.
Cars, as well as buildings,
fight for space on the ground.
It can be very difficult to move around.
By the beginning of the 21st century,
Shanghai streets were at maximum capacity.
A heavily congested eight-Lane highway
was the city's only link
to the Pudong international airport.
To get to the airport by car,
it takes 45 minutes.
You really need something to cut through the city
to get to the airport without stopping
and without encountering any other vehicles.
I, like most people in this city,
don't have time to sit in traffic.
China's solution...
The Shanghai Maglev, or transrapid...
A cutting-edge,
high-speed train, the fastest in the world.
The thing that's different and very unique
about the Maglev is the fact that it floats.
It hasn't got any wheels.
It floats across the guideway all the way to the airport.
Now the Maglev is just about to pull out of the station.
When it's at its top speed,
it'll be moving at 431 kilometers an hour.
That is just beyond belief, incredible.
To design a passenger train
capable of reaching 268 miles per hour,
the Maglev's engineering team had to toss out
many of the design features
we've come to associate with trains.
First, their train wouldn't have an engine.
Huh?
Then they would do away with one of engineering's
most fundamental inventions... The wheel.
Finally, they would defy the most basic laws of motion.
Ow!
Ooh!
Wow! Ooh!
But before engineers could design
their futuristic train with no engine or wheels,
they had to figure out a way to fit it
into the already overcrowded streets of Shanghai.
Shanghai is one of
the most heavily populated cities in the world,
and the population is increasing.
Now, building the infrastructure it needs is very challenging
just because there is no space.
Like all the buildings around here,
the only place really to build is to go up.
Chicago is one of the world's busiest cities.
The logistical challenge of moving around its inhabitants
is a daunting task...
But the city's early planners came up with an idea
over 100 years ago that still keeps the city moving today.
In the late 19th century,
Chicago is one of the fastest-growing cities,
if not the fastest-growing city in the world.
In the 1840s,
shortly after the city was established,
we had roughly about 4,000 people.
And by 1900, we've got over a million and a half.
Our city is rapidly expanding.
It's almost the Shanghai of the late 19th century.
So, how did engineers
and planners deal with the need
to transport the city's growing population
without clogging the busy city streets even further?
So this is the solution that was developed,
to elevate the city's rail lines above the street traffic.
Although it's not cheap to do this type of infrastructure,
it is cheaper, of course, than building subways.
Work began on Chicago's train in 1892...
But building tracks 30 feet above
the city streets was not welcomed by everybody.
Third-floor apartment tenants
now had to keep their curtains closed if they wanted privacy,
and young women were warned to be careful
of roving, railborne Peeping Toms.
Nevertheless, the system was a big hit for most.
It was lovingly nicknamed the "I," short for elevated.
We're here at Quincy.
This "I" station has been restored,
and it gives us a sense of what commuters would have seen
in the late 1890s.
And the basic concept of moving people in and out of the city
at a different level
than street level has not changed since then.
Elevating the city's train
was a solution so successful
that, more than 120 years later,
the "I" is still transporting
a half-million passengers each day.
The growth of the "I"
and the growth of Chicago are synonymous.
The boom of population
in the late 19th century follows right along
with the growth of this transit system.
And I don't think, without the "I," we would have had
this great, vibrant American city that we have today.
Engineers of the Shanghai Maglev
are taking Chicago's idea
of an elevated passenger train...
Ooh!
That was fast.
...And giving it a 21st century twist.
Engineers of the Shanghai Maglev
have taken Chicago's century-old solution
of an elevated railroad and created their own
19-mile guideway high above the city streets.
The advantage a system like this has
in already built-up urban spaces
is it's very easy to install.
It doesn't interfere
with underground services.
It doesn't interfere with existing
infrastructure at ground level, which is really good.
But building an elevated guideway
in this part of the world
came with some unique challenges.
Shanghai sits in an area of great seismic activity.
It also has weak Clay soil.
The risk of liquefaction is very high.
Liquefaction is an unusual
and dramatic phenomenon
that can occur during an earthquake,
when solid ground turns to mush.
Aah!
Physicist Andrew Steele
has prepared a simple demonstration
to show how liquefaction works.
So this water represents the groundwater.
This ground has got a very high water table,
so it's only got a thin layer
of dry soil on top of the saturated soil underneath.
So, imagine you build on this land,
you construct your beautiful city.
But you built on Sandy soil,
and you build on a fault line.
So there's the danger of an earthquake.
You can see that, as you shake it,
then the groundwater is forced up
into the top layer of the soil, and that changes its state
from that of a solid to very much behaving like a liquid,
and the buildings are just sinking straight into it.
Earthquakes are a constant threat in Shanghai.
If the ground liquefies, the Maglev's designers
had to ensure the tracks
wouldn't sink into the soft soil.
So engineers developed a technique called piling.
They built each support pier on top of a giant concrete cap.
Underneath the caps are concrete piles,
which are driven 200 feet into the ground.
If the soil near the surface liquefies,
the deep roots will hold the Maglev's track in place.
In less than nine months,
Chinese engineers constructed over 2,500 concrete columns
to support the guideway.
This would be the fastest train in the world.
But trying to get a train up to speeds
pushing 500 kilometers an hour,
designers would be faced with the problem
of wind resistance or drag.
The greater the speed, the greater the resistance.
And all this air movement has
the potential effect of slowing the train down
and wasting valuable energy.
To build a train
that can break 300 miles per hour,
engineers had to look back
to the great innovations of the past for the solution.
The earliest evidence of railroads
can be traced back to ancient Greece.
Men and animals pulled wheeled vehicles in limestone grooves.
The grooves prevented the wagons
from leaving their intended route.
Railroads were developed as a way of reducing friction.
In 1805, the English discovered that a good horse
on an ordinary road could pull a wagon weighing a ton.
But on rails, that same horse could pull
12 wagons each weighing three tons for six miles
in just two hours.
Oh.
When steam power was introduced,
continents could be crossed with ease,
transforming the modern world.
Railroads dramatically changed the way we live.
But throughout the 19th and early 20th century,
train design was at a standstill.
Train design fundamentally hadn't changed for 100 years
since this, stephenson's rocket.
You can see the classic cylindrical boiler.
We got a smokestack at the front,
and its completely snubbed, flat, unaerodynamic nose.
It would take a radical thinker
to shake things up.
And in the 1930s, england steam locomotive engineer
Nigel Gresley designed a new, sleek machine that would,
at the time, be the fastest train in the world...
The Mallard.
Everything about this locomotive is designed to go
as fast as possible.
You've got these massive wheels driving it forward.
We've got a double chimney to suck out the exhaust
as quickly as possible at high speed,
and then you've got this beautiful streamlined shape
in stark contrast to the trains that had come before.
Gresley used a wind tunnel
to develop the Mallard.
Wind tunnels had been used on planes
but never on a train before.
He made some interesting discoveries.
Andrew Steele is visiting a test center called the train rig
to see firsthand the difference
a streamlined train design can create.
This is the test track. It's 150 meters long,
and we can accelerate trains to 75 meters a second,
which is over 250 kilometers an hour.
Today we've got two different trains
that we're going to be testing.
This is a flat-nosed freight train,
which represents sort of an unaerodynamic train
as they were originally designed.
And this one here is a high-speed train.
Got this sloped nose.
We're going to see what difference that makes
to the speed the train can travel at.
And this is what we're going to be using
for the actual experiment.
These things here are light gates.
And when the train goes past this one,
it interrupts the light beam, and we can detect that time.
Then, a fraction of a second later,
it'll go past this light gate, interrupts this beam,
and by measuring the difference between two times,
we know this distance here,
so we can work out exactly how fast it's going.
The model trains are fired
using giant rubber catapults.
So I was just applying some tension to the track now,
and that's pulling the train back into the firing position.
I'm almost as tense as the train is.
Okay.
So just... Here goes.
Ooh!
That was fast.
Ooh!
And believe it or not,
that was a sort of slow test run.
So now that we've done that test run,
the key thing is to find out the readings that we got
from these light meters.
We've got two readings here.
At the first set of light gates,
it was doing about 36 meters per second.
But then, by the time the second set of light gates,
just a couple of meters later, it's only doing 34 1/2 meters
a second, so you can see it's lost some speed,
the aerodynamic drag has kicked in
and slowed the train down.
In the short distance between gates,
the flat-nosed train loses around 5% of its speed.
Next to be tested is the sloping-nosed model.
Ready, aim, and fire.
Phew!
Wow.
Oh.
The sloping-nosed model's speed reduces by only 2%
between the light gates.
Phew!
So these numbers, they're quite subtly different.
But when you scale it up to a full-sized train
and you're looking to propel it constantly down the track,
this can translate into a big change of efficiency.
A fact
Nigel Gresley discovered while designing the Mallard
and exploited brilliantly.
Gresley's engineering really was
a complete step change.
Although we'd used aerodynamics in planes
and hydrodynamics was known about in boats,
this was the first time
those principles had been applied to a train.
And that is what enabled the Mallard
to travel at 126 miles per hour.
In 1938, the Mallard set the record
for the fastest steam train on rails,
a record which still stands today.
The designers of the Shanghai Maglev
have learned from the breakthroughs
made by the Mallard and created a train
that travels at speeds that innovator Nigel Gresley
would have thought to be impossible.
In one test run, it exceeded 300 miles per hour...
Almost three times what the Mallard was capable of.
You can see it has a very sleek,
streamlined design
with a very smooth, sloping nose.
Also the train wraps itself around the guideway
which reduces turbulence that might otherwise be generated
between the train and the track.
But to build
the fastest passenger train on the planet,
engineers would need more than just an aerodynamic design,
so they drew inspiration
from a decades-old engineering experiment...
They combined the principle of the hovercraft
and a jet engine,
and they smashed the rail speed record.
...To create their own impossible engineering.
The Shanghai Maglev
is the fastest passenger train on the planet.
It travels at an astonishing top operating speed
of 268 miles per hour.
The train has transformed travel
between downtown Shanghai and Pudong airport.
The Maglev runs
all the way from here to Pudong airport,
which is a 34-kilometer journey in that direction.
Now if I was to get the Metro,
it would take me over an hour.
If I got a cab, it would take me 40 minutes or so.
But if I got the Maglev, which I like to do,
it takes me only seven minutes.
But the development
of the futuristic Maglev took decades of experimentation
before it reached its incredible 21st century performance levels.
Created in Germany,
the first passenger-carrying prototype,
the transrapid Maglev system, was unveiled
in 1971.
It traveled at speeds
where little consideration to aerodynamics was necessary.
But as experiments continued
and speeds rapidly increased,
the train car design that now graces
Shanghai's elevated track took shape.
However, increased speed
means increased engineering challenges.
The Maglev going to the airport
and the Maglev coming from the airport
pass each other at incredible speeds,
potentially a combined speed of over
860 kilometers per hour.
And this could cause a potential problem.
However sleek the design,
any object passing another at speed
creates a change in pressure between them.
Lower pressure, as the trains are together,
followed by a return to a higher pressure once they've passed.
This could potentially cause stresses to the cabin walls.
So maglevs have been engineered
with an aluminium composite shell,
light, but at the same time, strong and stiff enough
to support the pressure
acting on the structure by high-speed traveling.
But there were other design elements
that the Maglev's engineers had to consider
if they wanted their train to achieve record-breaking speeds.
It's not just the wind
that provides friction on the train.
One of the biggest losses of energy
that occurs in a traditional train
is produced by the friction
between the wheels and the track.
The more friction there is, the more power is lost.
In a car like this, for example,
1/3 of the fuel is spent on overcoming friction.
To limit the negative effects of friction,
engineers designed the Maglev in a way
that only some of history's most daring engineers have attempted.
Physicist Andrew Steele is in
the French countryside looking for the remains of a system
that could have been just as revolutionary
as the Maglev.
So here it is, over 50 years old and covered in moss.
This is what its creators thought would be
the future of high-speed mass transit...
A single concrete rail, straddled by a train,
capable of traveling
at 422 kilometers an hour, at a time
when the speed record for a conventional train
was just half that.
So what kind of vehicle
was capable of overcoming the forces of friction
to travel over 250 miles per hour?
The answer lies in a closely guarded warehouse.
I've come to a top-secret location
somewhere outside Paris
to get a rare look at what could have been
the future of land transportation.
Hello. Good morning.
So, where's it kept?
Hidden among
an assortment of military vehicles
are the last surviving examples of an extraordinary experiment.
Wow.
So this is the Aérotrain. Yes.
It looks like something out of the future.
Designed by engineer Jean Bertin in the 1960s,
the Aérotrain 01 and 02 are the only surviving prototypes
of a system that hoped to change train travel forever.
You can see the Aérotrain doesn't have any wheels.
Now that might seem strange,
but although the wheels have been the basis
for land transport for thousands of years,
they come with a big disadvantage,
because the wheels rub against the ground.
They create friction,
and the Aérotrain tries to get around that.
Engineers and scientists have been toying with the idea
of frictionless travel for some time.
The idea is that, if you can remove
that frictional resistance to motion,
then you can make things travel faster and more efficiently.
The simplest way to do that might be
to levitate it on a cushion of air,
and that's the principle behind how a hovercraft works.
We've got our own very simple model of a hovercraft here.
It's just a cd with the top of a drinks bottle on it
and then a balloon.
Before we inject that cushion of air,
the cd only moves a very small distance across the table
when I tap it.
However, what we can do
is attach a balloon to this drinks bottle top
and see if that makes any difference
to the way that the cd moves.
So here we go.
You can see that now, with a tiny tap,
the cd moves a long way.
And just as long as the balloon has got some pressure
to force that air down underneath the cd,
then it'll keep on moving around freely.
But when the balloon runs out, of course,
the cushion of air vanishes and the cd is just as hard
to move across the table as it was before.
In here, we've got the guts of the Aérotrain.
And incredibly, there were just two regular
car engines which power massive fans.
And that blasts air downwards
to lift the train up off the ground and then inwards
to keep it centered on the track.
That means the train isn't in contact with the ground
or the track, and so that source of friction is removed,
and that means that more of the energy
from this engine up here,
the propeller, can be used to power the train
to move forwards.
It's 11 meters long, weighs 2.6 tons,
and yet the air gushing out of these nozzles
is enough to keep it floating two or three millimeters
above the track.
By 1967,
the Aérotrain was proving its potential
on the test track as the next generation
of passenger transport.
A plan to build a track
for the Aérotrain between Paris and Orléans...
65 miles in 35 minutes.
For Aérotrain mark 02,
Jean Bertin went all out for speed.
The Aérotrain 02
was a futuristic combo of fighter jet, race car,
train, and hovercraft.
It looks like something out of a Sci-Fi movie,
but the technology itself is actually pretty simple.
I think my favorite control
is this one that goes marché and arret.
So it's basically stop and go just by flicking a switch.
Nevertheless, it was the combination
of engineering ideas
that made Jean Bertin's Aérotrain groundbreaking.
Bertin's ideas really were revolutionary.
They combined the principle of the hovercraft and a jet engine.
This was the first time it had ever been done.
Combined, they smashed the rail speed record.
An aircraft jet engine gives initial thrust
up to speeds of around 185 miles per hour.
An additional rocket motor boosts the mph to 235.
Sadly,
Jean Bertin's dream of friction-free travel
died in the 1970s
when the French government abandoned the experiment.
But almost a half century later,
the Aérotrain has a familiar-looking cousin
over 3,000 miles away in China.
The Shanghai Maglev...
The world's fastest passenger train,
a unique engineering feat
situated in one of China's most ambitious cities.
This Maglev here is the only
high-speed Maglev in the world, and that kind of
chimes in with the ambition of Shanghai.
People come here to design daring buildings
and daring systems.
And one of the most daring of them all
is the Maglev...
Traveling at a staggering 268 miles per hour,
appearing to defy physics.
The first time I traveled in the Maglev,
we hit 400, and I thought, "oh, my goodness."
And then it continued to travel even faster.
I could not believe what I was seeing and experiencing.
And it is currently doing a top speed,
flying pretty much at 431 kilometers an hour.
And it still feels very comfortable
for the speed at which it's traveling.
The Maglev is faster than the formula one car.
It is flying along.
The Maglev's record- breaking speed is possible
because it's levitated above the track
by powerful electromagnets
instead of a hovercraft design like the French Aérotrain.
But levitating a train with magnets
would be impossible without one of science's great innovators.
Born in 1791,
Michael Faraday was the son of a blacksmith
and received little formal education,
but he would go on to revolutionize
the engineering world.
His original laboratory
still exists at London's royal institution...
I'm going to give it a little push.
Where physicist Andrew Steele
is exploring how Faraday's discoveries
made magnetic levitation possible.
Faraday's discoveries revolutionized
our understanding of the interplay
between electricity and magnetism.
And one of the things that this understanding allows us to make
is an electromagnet.
So an electromagnet is made of a coil of wire.
You then need to get the ends of those pieces of wire
and plug them into a power supply.
And, finally, to magnify the magnetic effect,
you often place a core of a material like iron
in the middle of the magnet.
Let's connect this up.
And to prove to you that that's magnetic,
you can see...
That even with this extremely simple setup,
we can actually get a piece of metal to stick to it.
Another crucial factor about electromagnets,
if you want to use them for levitation,
is that we can change their strength,
and we can do that very easily.
Just by changing the electric current
passing through this magnet,
I can turn the current down
and make the attraction much weaker.
Or I can turn the current up and make that attraction
get stronger again.
Not only can electromagnets be adjusted
and turned on or off at will,
but they're also significantly stronger than ordinary magnets.
If you want to suspend an entire train,
you're going to need a pretty powerful electromagnet.
And actually, electromagnets are pretty strong.
This little one is enough to suspend my entire body weight.
And actually,
this thing needs surprisingly little electric current.
There's less electricity flowing through this device
than there is through your hair dryer or your kettle at home.
We've got an electrical current
flowing through this electromagnet.
If we connect it to the piece of metal on my back,
then, hopefully, there should be enough strength
to hold me above the floor.
And there you have it.
On the Shanghai Maglev,
powerful electromagnets
are installed into the underside of the train cars,
allowing them to float.
Guidance magnets keep the train centered,
and support magnets pull the unit
to the underside of the track, lifting the train above.
The entire train floats,
suspended 10 millimeters below the track.
Not only does this reduce wear and tear,
but it also makes for
extremely fast, friction-free travel.
Because there's no contact
between the train and the guideway,
there is no friction, and this means that the train
can have a lifetime of up to 50 years
with minimum maintenance required.
But while designing
China's futuristic passenger train,
developers couldn't just focus on speed.
They had to ensure the Maglev
was environmentally friendly, too.
China, like all modern economies,
is worried about its carbon emission quota.
As development continues,
the demand for oil will also likely increase,
but China has a limited domestic oil supply.
With its current gas-guzzling congestion problems,
greener transport initiatives are drastically needed.
Otherwise, the city will choke.
Their environmentally friendly solution
came from one of history's great engineering innovators.
In the late 1940s,
a British engineer's groundbreaking experiment
would earn him the nickname
"the father of the Maglev."
This is a sheet of aluminium.
When I put it on the motor and switch on the magnets,
something pretty dramatic occurs.
Electrical genius Eric laithwaite
developed the first practical linear electric motor,
creating an effect he later dubbed the magnetic river.
First of all, it will levitate,
or support, an aluminium plate.
It will guide it sideways,
and it will also propel it along.
The linear motor
takes a traditional coiled electric motor and unrolls it.
Instead of spinning a rotor, what was the coil, or stator,
provides a bed that drives the object along its length.
And there you have your modern
vehicle being guided, lifted, and propelled,
all by means of the same set of coils.
Laithwaite's experiments
provided the key that unlocked the potential of the Maglev.
The builders of the transrapid Maglev system
constructed a series of stator blocks.
They are the main component of the linear motor
and act as the propulsion system for the train.
Once installed, they were tested in Germany,
and in combination with the support
and guidance magnets, enabled the Shanghai Maglev to levitate.
The train can travel over 300 miles an hour
without an on board engine.
A linear motor is embedded into the guideways.
But don't be fooled
into thinking this whole track is electrified all the time.
What is so brilliant about this system
is that only the sections of the track
on which the vehicle moves
is powered at any time.
So as it sets off, the track ahead of it is dormant,
and only the section in front of the Maglev turns on.
As soon as the Maglev has passed over the short section of track,
it turns off again,
as the job of pushing the Maglev along is taken up
by the next section of track.
And so on and so on, all the way to its destination.
But with less than six inches
between the Maglev and its guideway,
even the slightest malfunction could be catastrophic.
It is critical to maintain
an even gap between the train and the track,
no matter how many passengers are on board.
To do this, the Maglev's builders
had to create one last piece of impossible engineering.
Traveling at an astonishing
268 miles per hour
while floating on a magnetic field,
the Shanghai Maglev is the only high-speed train of its kind
operating commercially in the world.
But having a levitating train fly through Shanghai
at such high speeds comes with several engineering challenges.
There is a carriage hurtling along
at over 430 kilometers per hour.
So it is critical to control
fluctuations in the magnetic field
and maintain an even gap
between the train and the track,
no matter how many passengers are on board
or what variations there are in the load it's carrying.
With just six inches between
the Maglev and its guideway, any errors could see the train
crunch into the track.
The engineering team's solution,
as physicist Andrew Steele demonstrates,
relies on sensors constantly regulating
the current flowing through the electromagnets.
There we go.
You can see this permanent magnet
is suspended underneath this electromagnet.
Whenever the permanent magnet moves
slightly imperceptibly closer,
this little sensor on the bottom here detects that,
sends a message down to these electronics,
and tells the electromagnet to become a little bit weaker.
It turns down the current.
That allows the ball to fall away a little bit.
As it falls away, the sensor detects that again
and increases the strength of the electromagnet
and pulls the ball back towards it.
So one complication of this system
is that your feedback system always needs to be working,
and it needs to be working very fast.
You can see this ball
is spinning and wobbling a tiny bit,
and that's fine for a little demonstration like this.
But if you got a train traveling
at hundreds of kilometers an hour along the track,
you're going to need a very, very sensitive
and accurate feedback system.
The Shanghai Maglev
takes this simple concept to a whole new level.
There are 128 sensors in each section of the Maglev vehicle.
They feed back the distance between magnets and track
thousands of times a second.
Powerful computers adjust the electromagnet's current
constantly with microscopic accuracy.
This is the guideway,
and the train floats one centimeter from the guideway.
Now, that is incredible precision.
Now, there's a computer system that makes sure
that, all of the time, the train floats
at one centimeter from the guideway.
An advanced computer system
regulates the operation of the train service.
Each journey's travel time is predictable to the second.
Now, this is the ambition of the Maglev,
with computer systems
able to achieve an extremely precise service.
It's taken decades of planning,
design, and testing to create
the world's only commercially operating high-speed Maglev.
It's a unique concept that throws away the rule book
for traditional train travel
and makes high-speed journeys possible in engineless vehicles.
A system like the Maglev
points to the future of transport in our world,
incredible things to be achieved.
This shows us that we can get people moving
from "a" to "b" in short periods of time,
which is great.
By drawing on the innovations of the past,
adapting, improving them,
and making breakthroughs of their own,
the designers and engineers
of the Shanghai Maglev
have realized the dream of a super-fast train
that flies without wings
and have succeeded in making the impossible...
Possible.
It's kind of unbelievable
that there's a train that goes over 400 kilometers an hour.
It is a vision of the future,
and it's here right now.