Original subtitles

This time on "Impossible Engineering,"

the highest railway ever built...

The engineering is mind-blowing.

It was almost impossible

to conceive of a railway running at this altitude.

Constructed in a remote, frozen wilderness...

It's definitely amazing.

It's a totally different setting.

And the pioneering, historic innovations...

We're at 30 meters.

One of the biggest changes is my voice.

I speak in a very strange manner.

I can sense the lack of oxygen through my lungs.

Lightheaded. Do not feel great.

That made the impossible possible.

Captions by vitac... www.Vitac.Com

captions paid for by discovery communications

this is Lhasa,

the spiritual home of Tibetan Buddhism.

This city in the clouds is one of the highest,

most inaccessible on earth.

Situated on the vast Tibetan plateau,

it is surrounded by not one

but three mighty mountain ranges.

Before the 1950s, there weren't even any roads

to get to Lhasa... Just meandering mountain paths

that took months to get through, and only in good weather.

But the Chinese government came up with an audacious scheme

to connect this ancient province with modern China.

This is the highest railroad on the planet.

Specially-designed, high-altitude trains

climb to 16,400 feet above sea level

to cross the Tibetan plateau...

The highest and largest mountain plateau on earth.

Our locomotives can pull 3,700 tons of cargo

or 20 passenger carriages.

It's the most advanced technology in our country.

The engineering is extraordinary.

675 Bridges and 10 tunnels

to cross the frozen wilderness

that's known as "the roof of the world."

Whenever I see the train passing through the Tibetan plateau,

I feel extremely proud.

From Beijing and Shanghai in the east,

trains run to the city of Golmud,

the start of the high-altitude line.

From here, they begin their climb,

crossing the formerly impenetrable Kunlun mountains

to reach the immense, frozen Tibetan plateau.

At this altitude,

the air oxygen content is half that at sea level,

and temperatures can drop below negative 20 degrees.

The railroad reaches the world's highest station

at the Tanggula pass,

a staggering 16,600 feet above sea level,

before making its way to Lhasa.

This is the Qinghai-Tibet line,

a railway which at first people thought was impossible.

It's called the heaven road,

and, honestly, that's what it is.

It's the most audacious railway project ever imagined,

so it comes with some enormous challenges.

Perhaps the biggest challenge

is how do you keep everyone breathing?

At this incredible altitude,

oxygen is in short supply.

Dr. Zhu Xinxiang is in charge

of the railway's medical unit.

On the Qinghai-Tibet railway

between Golmud and Lhasa,

the average altitude is over 4,000 meters.

It's an area of extremely low atmospheric pressure.

There's only around 50% oxygen in the air here

compared with the mainland.

The human body is not designed to cope

with such low oxygen levels.

It can lead to potentially fatal altitude sickness.

In severe cases where the body's starved of oxygen,

it can cause swelling of the brain or lungs,

which can be fatal.

These unique trains are specially engineered

to protect their passengers

as they travel through this beautiful but brutal landscape.

Ding Weiran is the senior engineer.

In here is the oxygen generator,

which pumps oxygen into the train carriages.

These prevent oxygen shortages at high altitude

and make passengers feel more comfortable.

Inside, there is an altitude sensor to determine

the oxygen levels outside, and oxygen concentrations sensors

to monitor the levels in each passenger compartment.

The train is made up of 16 carriages,

and each of these carriages

has its own oxygen generator like this.

The passengers also have access to oxygen masks,

which they can use if they're having difficulties.

Well, if you're just sitting here, then it's all right,

but if I climb to the top of the bunk bed,

then I notice that I have some shortness of breath.

As an extra precaution,

the railroad posts a medical team on every train.

These extra measures onboard ensure safe passage

for the 2 million travelers who make the journey every year.

But the team that built the line didn't have these luxuries.

Construction workers are at a high risk

of altitude sickness and hypoxia...

A severe lack of oxygen. Doing physical work

means your body uses up oxygen very quickly.

That made this an extremely difficult project.

At first, we thought there was no way it could be completed.

They would need to turn to a machine from the past

to defy nature and build across the roof of the world.

Dr. Gary Smerdon is in southwest England

at the site of Isambard Brunel's masterpiece,

discovering how experts in engineering and medicine

came together to solve the problem.

So, here we have the royal Albert bridge,

a fantastic feat of engineering.

Most of the people who travel across the top of this bridge

do not have the faintest idea about the effort

and the suffering that went into building this bridge,

'cause the feat of engineering to get that pier built

down into the rock bed of the river

was very new at the time, very dangerous,

and they didn't really understand what they were doing.

These workers were moving into a pressurized environment

every day to do their digging and their engineering,

then coming back to the surface.

There were 25 workers. One died, two became paraplegic,

and all of the others became ill

due to what became known as caisson disease.

With 19th-century engineers

wanting to build ever more impressive structures,

a way to treat workers who came down with caissons disease

had to be found.

In 1876, American inventor Daniel Kelly

submitted a patent in Chicago for a compressed-air bath,

a machine that would hold the key

to treating workers with caissons disease...

Today commonly referred to as decompression sickness

or the bends.

The body contains nitrogen gas.

When the pressure increases,

this gas dissolves into the blood and tissue.

But when the body returns to normal pressure,

it becomes a gas again.

If bubbles of nitrogen gas form, they can gather in joints

and tissues, causing serious problems.

Kelly's machine was a forerunner

of the hyperbaric chamber.

Any problems, just put your hand up,

stay "stop," and we'll take it from there.

Lovely. See you on the surface.

While the condition affecting the caisson laborers

was very different

from what the Chinese workers were suffering from,

this amazing machine holds the key

to solving both problems.

An air compressor creates pressurized air,

which is stored in a giant tank.

It's slowly pumped into the hyperbaric chamber,

recreating whatever pressure environment

doctors need to treat their patients.

This was the key to treating caissons disease,

giving doctors the ability to reduce

those deadly bubbles in the blood.

So, here we are. We're in the chamber now.

The door is shut.

My colleague, Chris, is at the controls,

and he'll soon be pressurizing me

and getting me down to the equivalent of 30 meters.

And the machine itself can actually be used

to demonstrate the very problem it was built to solve

with a simple experiment.

So, with me here in the chamber, we have an empty bottle here

that's full of air

and another bottle that's full of carbonated water.

The empty bottle contains air

at normal sea-level air pressure.

So as the pressure in the chamber mounts,

the bottle collapses.

But that's not the only apparent change

in the pressurized chamber.

Okay, that's you at 30 meters, Gary.

Okay.

Gary's vocal chords are feeling the pressure, too.

And there we have a glass

of carbonated water.

The water, which was carbonated at normal air pressure,

has completely lost its fizz.

That much pressure, the gas molecules

are dissolved in the liquid, but the gas is still in there.

This water represents blood in the body.

So when we go back to the surface, you will see,

bubbles will start to appear.

That's exactly what was happening

to these caisson workers,

where bubbles will start to appear in your blood

and in your tissues. As a human, you're in trouble.

It was discovered that the key

to keeping bubbles from forming

was a slow ascent,

giving the body time to equalize.

This machine allowed doctors to simulate a slower,

controlled ascent, saving the lives of caisson workers.

Likewise, the engineers behind the Qinghai-Tibet railway

will take inspiration

from Kelly's rudimentary hyperbaric chamber

to protect the workers

constructing this impossible railroad.

In China, the team

building the Qinghai-Tibet railway

realized that Daniel Kelly's 150-year-old

air-compressing chamber could be put to a different use.

On the 29th of June, 2001,

the build began of the highest section of the railway.

This was the base hospital for the construction team.

We provided a lot of medical personnel and support.

This hyperbaric chamber was used frequently.

The construction team went through 120,000 bottles

of oxygen each year, but even that wasn't enough.

There were many critically ill patients

during the construction of the railway.

These chambers were vital.

They saved patients' lives.

When you're working at 4,000 meters altitude,

getting back down to sea level isn't easy.

But by placing workers suffering from altitude sickness

into hyperbaric chambers, they could effectively simulate

a move straight back down to sea level,

meaning treatment could start immediately.

Engineers installed 25 chambers

at strategic locations along the line.

During the construction of the railway,

the success rate for saving lives

from acute altitude sickness was 100%.

There were no fatalities.

This line is a milestone in the history of railways.

I'm proud of it, and I'm very proud

of being part of the medical team during its construction.

This machine helped keep the 100,000 workers,

who spent five years

building this inspirational railroad, safe.

Mount Everest is the highest mountain in the world,

with the Himalayas making up the Southern edge

of the world's largest mountain plateau.

Stretching 620 miles north,

the Tibetan plateau is the breathtaking setting

for the highest railroad on earth.

In the past, people thought a railway to Lhasa

could never be done.

It's one of the most remote cities in the world,

but this didn't stop the Chinese engineers,

and the engineering challenges they faced were immense.

The city of Golmud sits at over 9,000 feet

in the foothills of the Kunlun mountains.

To link it to Lhasa,

engineers needed to find a way to run rails

across the permafrost, permanently frozen ground

of the 965,000-square-mile plateau beyond.

Wang Jinchang is professor of engineering

at the railways research institute

that was tasked with achieving the impossible.

He regularly makes the 8-hour round trip from Golmud

to the heart of the plateau

to monitor the ground conditions.

The area we're in now is typical of the Tibetan plateau.

It's called "no man's land."

2 or 3 meters beneath us is permafrost,

which is permanently frozen ground.

It's incredibly cold here.

Building anything in this environment isn't easy.

Frozen ground can actually provide

the perfect foundation for building on,

but with one important condition...

It must remain frozen.

If the ground melts below your foundations,

you're in real trouble.

A railway line is at risk of collapse,

derailing any trains trying to use it.

So how do you keep hundreds of miles of ground

frozen solid enough to build on?

For inspiration, the engineers turn to another frozen territory

4,300 miles away.

Known as the last frontier,

Alaska is America’s northernmost state.

Straddling the arctic circle,

it covers a staggering 656,300 square miles.

When the largest oil field in north America

was discovered in Prudhoe bay,

an 807-mile pipeline down to the Southern port of Valdez

was required to export the oil.

The problem, just like in Tibet, was that they needed to build

on endless expanses of hard but unstable permafrost.

Local civil engineer Doug Goering

is aware of just how hard this can be.

Trying to build any kind of engineering structure

on this type of permafrost results in major challenges.

If you try to build a warm structure like a house

or a building, you can imagine that the heat from that building

is gonna work its way into the ground.

It thaws the ice in that ground out,

and it becomes a mushy mess.

The house foundation typically fails.

And when you're trying to build a pipeline

that will carry warm oil, those problems are compounded.

Normally, an oil pipeline would be buried,

but anywhere where the ground is frozen,

the pipe has to be physically separated from that frozen soil

because, of course, it carries warm oil.

That warm oil would melt the frozen ground

and cause structural problems...

Cause the pipe to deform, buckle,

and probably would have caused oil leaks.

So they built it above ground.

This is the trans-Alaska pipeline...

An $8 billion creation

that carries up to 2 million barrels of oil a day

across the entire state.

The design focused on an elevated pipeline

to keep the warm pipe away from that frozen ground.

But the foundations for the support columns

still needed to rest on solid, frozen ground.

If it melted, whole sections of pipeline could collapse.

Luckily, one man had an answer.

In 1963, nuclear physicist George Grover

developed a system to transfer heat

that would be crucial

for engineers trying to build on permafrost.

You can see that each of these vertical support members

are capped by two finned sections.

Those fins sit on top of a device known as a thermosyphon.

These thermosyphons are used to ensure that the ground

that the vertical support members go into remains frozen.

The vertical support members rely

on that frozen ground strength to hold the pipe up.

A thermosyphon is essentially an empty tube

which goes through the marshy bog down to the frozen ground.

At its base is a liquid refrigerant

with a low boiling point.

When the temperature rises in the ground,

the liquid absorbs the heat, starts to boil,

and then evaporates,

dissipating the unwanted heat through the tube

and into the atmosphere,

keeping the ground around the foundations cool.

What I have here is a canister of butane,

which is similar to the refrigerant

that's used in the thermosyphon.

And what I'm gonna do here for a demonstration

is get a little bit of liquid butane into this plastic bag.

So you can see that I have liquid in the bag, here.

What happens at the base of the thermosyphon

is that liquid boils.

And you can see that when I add heat

by putting my fingers on this bag,

that I get pretty vigorous boiling of the butane.

This is the same thing that's happening

at the base of the thermosyphon.

In this case, the butane is collecting heat from my fingers.

In the case of the thermosyphons,

the refrigerant collects heat from the permafrost

and pulls heat out of it...

Dumps that heat into the atmosphere.

Over 100,000 thermosyphons

help to keep the oil flowing.

This pipeline project really is an engineering marvel.

It's been stable for on the order of 40 years.

Really, I think it's safe to say that the engineers

who designed this solved the permafrost challenge.

The permafrost challenge has not beaten the team

in Tibet, either.

Here, they've used thermosyphons on a massive scale,

stretching as far as the eye can see

to cross over 310 miles of permafrost.

These thermosyphons are the best way to solve the problem.

It's a great solution.

Its main function is to decrease the temperature of the ground

and prevent the permafrost from melting.

This is the part that releases heat.

This is the middle section,

and the working part is underground.

We use two rows of thermosyphons on the side facing the sun

and one row on the side which doesn't face the sun.

Over 25,000 thermosyphons have been installed.

But with the heat generated from passing trains,

the thermosyphons alone aren't enough to keep the ground frozen

and the foundation solid.

The track is also raised off the ground

on a crushed rock embankment.

This low-tech engineering works by letting the cold wind

flow through the gaps between the rocks,

dissipating any heat coming from the trains above.

By using these measures, we protect the railway

by keeping the ground cool up to 15 meters away from the track.

This prevents the permafrost from melting

and sinking the railway.

But for a 7.3-mile long stretch of the permafrost zone

in the heart of the plateau,

neither of these measures could help.

To make this unbuildable stretch buildable,

engineers would need to make the impossible possible.

We're now at the Chumaer river upland plain natural reserve.

This is all wetlands.

The biggest feature here is the hydrothermal lakes.

This is a natural occurrence of frozen soil.

While in the winter this area is frozen solid,

the heat from the hydrothermal lakes

means it's all a boggy marshland come summer.

So this is the incredible solution.

At over 6.8 miles,

it's the longest bridge over permafrost in the world.

Most of the frozen soil is melted here.

A rock embankment wouldn't be stable, so we built a bridge.

The bridge is supported by pile foundations,

which were inserted deeply into the ground.

In this environment, a bridge is a much better solution

than an embankment.

The biggest difficulty for us building this kind of bridge

is working in winter.

During summer, the atmospheric temperature is too high.

If we built during this season, we would risk

causing the permafrost to melt, making it too unstable.

Working through winter

at temperatures down to minus-22 degrees,

engineers achieved the impossible

and completed the final, most difficult part

of the line to Lhasa.

Building a railway

in the permafrost of the Tibetan plateau

was one of the biggest engineering challenges

in the world.

It was almost impossible to conceive of a railway

running at this altitude.

It's an extraordinary feat of human ingenuity.

To construct this $5.2 billion line

to run at high altitude,

engineers overcame huge hurdles,

but they also had to specially engineer the locomotive itself.

Across most of the China railway network,

electric locomotives are used,

which draw their power from overhead cables.

The Shanghai to Lhasa express uses these

for the first part of the 47-hour,

2.6-thousand-mile journey across the country.

But when the train reaches Golmud, it runs into trouble.

In the isolated, high-altitude plateau,

extremely low winter temperatures

combined with lightning storms

means that electricity supply cannot be guaranteed.

So they can't install the overhead cables

necessary to electric trains.

Normally, railroad engineers

would turn to a regular diesel locomotive.

Combustion engines need fuel and oxygen to work,

but at these altitudes, there's just not enough oxygen

to give enough power to the engines

to haul the huge trains up the steep gradients required.

Internal combustion engines draw air

into the combustion chamber to mix with fuel.

The piston compresses it. Then the spark plug ignites it.

This controlled explosion

forces the piston back down the cylinder.

But as oxygen levels drop,

so does the force of the explosion

and the power produced.

Regular locomotives just wouldn't be able to cope

with the lack of oxygen.

They wouldn't get anywhere near Lhasa.

To get trains to run at such high altitudes,

the engineers needed to look to the skies.

Mechanical engineer Dan Dickrell is exploring pikes peak,

one of the highest points in the rocky mountains.

It was here in 1918 that a landmark experiment

changed engine design forever.

Driving this really muscley car

up one of America’s most iconic highways

is quite exciting from both an engineering

and an auto-enthusiast perspective.

But as the road climbs,

the amount of oxygen in the air falls.

I've reached the halfway point up pikes peak.

I can feel that lack of oxygen at this altitude,

and so the automobile.

At the bottom, it was really snappy.

It's starting to get a little bit more sluggish.

At the 14,115-foot summit,

the oxygen is almost 50% lower than at sea level.

All right.

I can really, really feel it.

Lightheaded. Do not feel great.

And on the way up,

the internal combustion engine inside my car,

it could feel it, too.

This problem plagued early aircraft pioneers,

who found the higher they took their machines,

the more their engine's power faded.

And during world war I, the ability to fly high

became a matter of life and death.

The higher a plane could get,

the smaller the chance of it being detected by the enemy.

They had to find a way for their engines

to cope with lower oxygen levels

so they could go higher than ever before.

And the solution they landed on

just might hold the answers for the team in China.

For a solution to their low-oxygen, high-power needs,

the engineers behind the Qinghai-Tibet railway

must turn to an innovator of the past.

During world war ii,

aircraft designers needed to maintain engine power

at increasingly high altitudes to avoid radar detection.

To help the U.S. air force solve their lofty problem,

they drafted in steam turbine engineer Sanford moss.

Sanford moss developed a revolutionary piece of machinery

that would force more air into the airplane engine,

essentially turbo-charging it.

Moss' turbocharger was a total game changer.

Instead of just being wasted, the engine's exhaust gas

is used to spin a turbine,

which in turn powers a compressor,

which draws in air, compresses it, cools it,

and pushes it into the combustion chamber.

This high-pressure mix, when ignited,

dramatically increases the engine's power.

To demonstrate the difference it makes,

first we need to see how an engine performs without it.

This is gonna serve as my cylinder.

Inside the cylinder, we're gonna put a mixture of fuel and air.

Instead of gasoline,

I'm gonna use butane.

Now, what I'm gonna do is I'm gonna take this butane...

And inject it into my cylinder...

And two metal electrodes are gonna serve as a spark plug.

I'm gonna introduce two alligator clips

that will provide electricity.

In three, two, one.

Cool.

All right, now we're gonna repeat the same demonstration,

except this time, I'm gonna turbo-charge the cylinder.

To do that, still need some fuel.

Now, this time, we're gonna introduce

a slightly different cork,

'cause this one as a valve in it.

That's gonna allow me to pressurize the cylinder,

just like a turbocharger would.

We lock down...

Give it a few good pumps...

And now I've got my pressurized cylinder.

Let's repeat

and see what the effect has on it.

In three, two, one, go!

Whoa! Nice!

Oh, that one flew much, much higher.

The turbocharged cylinder worked much better

in terms of explosive release of energy,

just like a turbocharged engine would.

In 1918, moss and his team came here

to carry out their first high-altitude test.

He put his new turbocharged engine on the back of a truck

and attached it to a giant propeller.

The output had been 230 horsepower.

But with his new invention,

it was boosted to 356 horsepower.

Three years afterwards, a biplane fitted

with a moss device broke the altitude record,

flying higher than any other airplane had flown before.

Turbochargers exist all over the place.

Really impressive pieces of technology.

In China, engineers have fitted moss' turbocharger

to special locomotives to give them the power

to cross the high-altitude Tibetan plateau.

At Golmud station, locomotive engineer Shen Dezhi

is supervising the switch-over.

This train has just arrived from Beijing to the east.

It's an electric locomotive,

powered from the overhead cables.

After the crew have disconnected all the wires,

it will be pulled out so that the new locomotive can come in.

With the passengers eager to continue

the next 14-hour leg of their journey to Lhasa,

the train crew must move quickly.

This is our solution to the high-altitude problem.

It's a tailor-made plateau diesel locomotive,

especially designed for the Qinghai-Tibet line.

It's about to be connected to these carriages.

These turbo diesel engines provide 6,000 horsepower

to pull either 20 passenger carriages

or a whopping 3,700 tons of freight

at speeds of up to 75 miles an hour.

I had the honor of driving the first train

to cross the plateau to Lhasa.

So whenever I see this incredible, advanced locomotive

coming into Golmud, I feel excited, very excited.

If we don't manage to build this turbocharged locomotive,

so many people just wouldn't be able to get to Lhasa.

I feel very proud of this solution.

But the engineers still face another major hurdle.

The single-line design

makes reliable communications essential.

With high-speed trains traveling in opposite directions

in some of the most remote locations on earth,

how do you ensure you can communicate with them

to keep them safe?

The highest railroad in the world

runs to Lhasa station.

Trains on this line are specially engineered

to cross the frozen tundra of the Tibetan plateau.

Undercarriages are sealed to protect against frost damage,

and even the windows are specially designed

to cope with subzero temperatures.

The windows are equipped with a special heating device.

It prevents the glass from freezing and cracking

as the train travels along the cold parts

of the Golmud to Lhasa line.

These incredible advances

make this previously impossible journey possible

for passengers like Gregor and Marianne, tourists from Holland.

Yeah, it's definitely amazing.

I'm reading a book right now

about a woman who's traveling in Tibet

I think about 20 years ago,

and it was so different.

You had to do everything by foot or with a Jeep.

And if there were mud floods,

then you couldn't go any further.

It's really a totally different setting

to just cruise through the mountains in warm trains.

The 710 miles of high-altitude railroad

between Golmud and Lhasa

includes a staggering 675 Bridges

and almost 6 miles of tunnels,

including the highest railroad tunnel in the world...

The 4,400-foot-long Fenghuoshan tunnel,

drilled through a permanently frozen mountain.

Building this line really pushed the boundaries of engineering.

But with a £3 billion price tag,

they simply couldn't afford to build two lines side-by-side,

one for each direction,

so they had to settle for a single line.

This presented engineers with a new challenge.

With high-speed trains traveling in opposite directions

in some of the most remote locations on earth,

how do you ensure you can communicate with them

to keep them safe?

So how could an innovation from 19th-century railroad pioneers

help inspire the engineers in China?

Engineer Kate Mulcahy is at miniatur wunderland

in the German city of Hamburg...

The largest model railroad in the world.

1,300 trains with over 10,000 carriages

crisscross this huge attraction,

where they have a similar problem...

Keeping trains safe.

Luckily, an ingenious, new form of technology

was about to change the way the world communicated,

setting in motion a telecommunications revolution.

In 1837, William Fothergill Cooke

and Charles Wheatstone struck upon a brilliant concept...

Electromagnetic deflection.

They found that when they created a complete circuit,

magnets reacted to each other predictably,

even across great distances.

Cooke and Wheatstone built this instrument...

The five-needle telegraph arranged on a grid of letters.

Now, in my version, my construction here,

this bit represents the sending element,

and then this bit over here

represents the receiving element.

These rods in the middle represent wires.

Now, because this telegraph, the sending one,

is connected in the circuit to this telegraph,

when I move this needle one way,

the action is mirrored in the receiving telegraph over here.

So, for example, if I wanted to spell out,

say, the word "stop," I start with the letter "s."

So, on my sending,

I'll move this needle so it points towards "s,"

and I'll move this needle so it points towards "s,"

and then the person on the receiving end

will look for where the points of those needles converge.

I then need to move the needles

so that I can get them to converge on "T."

This device enabled its users to spell out words

and send them down the wire.

Their feat of engineering brilliance

was to send the first communication

electronically on the railways.

The needle telegraph started a telecommunications revolution.

Adopted by the rail network initially,

it was quickly implemented worldwide.

In China, they've taken this 180-year-old concept

and given it a 21st-century makeover.

Third-generation railway man Wang Jinchang

manages the Golmud train station,

and the technology he uses to signal trains

on the Qinghai-Tibet railway is a far cry

from the 19th-century innovation that inspired it.

Between Golmud and Lhasa,

we use satellite positioning signals.

You won't see a single trackside signal on the Golmud-Lhasa line.

We use the satellite positioning signals

due to the tough weather conditions

and 4,000-meter-high altitude.

This is a great piece of technology.

It's a massive leap forward.

The train control system is run

from a control room at Xining station.

With global positioning satellites

determining the train locations,

all signaling is virtual instead of wayside signals

used by Cooke and Wheatstone's system.

All information is communicated directly into the train cab,

where an onboard computer terminal

displays up-to-the-second information to the driver.

The advanced technologies implemented along this line

are unique in this country.

They are the only reason that we can provide Tibet

with the heaven road railway that's been so important

for their economic growth and social development.

The Golmud-to-Lhasa line has transformed travel

across the Tibetan plateau.

Business increased quickly

once the Golmud-to-Lhasa line opened.

Just in the last year,

we've dispatched over a million passengers,

and the goods we have transported by rail

have sharply reduced the number of lorries on the road.

Lifestyle products, building materials,

and daily necessities such as oil

are basically all transported by rail now.

Building a railroad line across the roof of the world

was never going to be easy.

When we were young, we didn't think

there would ever be a railway between Golmud and Lhasa.

I think it's a milestone in the history of global railway.

The unprecedented and ambitious project

stands as testament to the tenacious perseverance

of the human spirit.

If this special locomotive didn't exist,

so many passengers wouldn't be able to get to Lhasa,

so I feel very proud of this train.

Go! Whoa! Nice!

By building on the work

of the inspirational pioneers of the past, upscaling,

and breaking new ground themselves,

the engineers have succeeded

in making the impossible possible.

The Qinghai-Tibet railway is the greatest engineering achievement

in the world.