The Assassin (Sha ren zhe Tang Zhan)

In this episode, the need for speed.

The unique challenges of making the world's railroads

run faster than ever...

When you see tiny, little pods moving at incredible speed

down these tubes, you can really see

why this could be the transport of the future.

And the ingenious solutions...

Without this fleet of trains,

the whole railway would grind to a halt.

That make the impossible possible.

It was to be among one of the fastest trains in America.

There's no doubt that this train captured the imagination.

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since the invention of railroads over 150 years ago,

engineers have been pushing boundaries in the quest

to reach the world's most remote locations.

Inspired by progress and the desire for adventure,

trains are continuously breaking records

and traveling further and higher than ever before.

But for train engineers, making engineers go faster

poses a unique set of challenges.

The problem is, every time you go twice as fast,

air resistance becomes about four times more of a problem.

We needed to make the network a safer place,

and at speeds that don't delay

other passengers or freight trains.

Compared to other forms of transportation,

trains are easier to access and provide travelers

a way to avoid traffic jams.

But in the quest to go faster,

hitting high speeds can mean compromising

something pretty crucial if you're a passenger.

Few countries' histories have been more strongly shaped

by its railroads than the U.S.

By the 1950s, advancements in the aerospace

and automobile industries

captured the nation's imagination.

Americans were now looking to the future of engineering

and not the past.

Engineer Dan Dickrell is in Missouri

to track down the train that was designed for speed.

This is a 1947 Cadillac and an amazing example

of American automobiles of the time.

People were falling in love with this car and cars like it.

Why would you want to be packed into a crowded train

when you could be riding in a magnificent vehicle

such as this?

By the 1950s, the train was increasingly seen

as a slow and uncomfortable way to get around,

leaving it in real danger of being left behind.

The task of revolutionizing train travel

fell to general motors' legendary designer Chuck Jordan.

His solution... the aerotrain.

Named the train of the future,

its bold design aimed to entice passengers

to get back on board, making traveling by rail faster

and more comfortable than ever before.

So, this is it.

It's the aerotrain.

It's an unbelievable train.

This train was the big bet.

This was the thing that was gonna save the industry,

revitalize it, and make trains cool again,

make you want to ride on it.

The aerotrain was designed to tap into

the public's enthusiasm

for the futuristic styles being used by car manufacturers.

Looking at the similarities

between the aerotrain and the Cadillac,

it's obvious, the influence... The nose, the streamlining.

It looks almost identical.

Taking inspiration from the roads,

the train's passenger cars

were designed like vehicles of the time.

But developers had more up their sleeves

than producing a train with just updated external features.

One of the solutions was materials.

It was gonna be made of aluminum,

which was revolutionary

because most trains of the time were made of steel.

This made it very, very light.

At around half the weight of a conventional train,

the aerotrain was a speed machine,

able to reach nearly 100 miles per hour.

It looks fast... That beautiful nose,

that sweeping windscreen.

The 1,200-horsepower engine could get it up

to speed very quickly.

But in reality, it was a huge failure.

Unfortunately, what the aerotrain gained in style,

it lacked in functionality.

The engineering doesn't hold up.

This area right here, this...

This beautiful curve actually acts like an air scoop.

Air is forced in with nowhere to go, slowing the train down.

So it's an example of where the designers wanted

some really, really powerful visual statements.

The engineering says, "mnh-mnh."

This beautiful shape actually makes this train

go a lot slower.

But aerodynamics

wasn't the aerotrain's only issue.

The train's lightweight body led to some unfortunate consequences

for the passengers on board.

There was a big problem...

The cars themselves were so light

that the wheels had a hard time

staying on the rails at top speed,

so the passengers inside would be bounced around

like basketballs.

A problem intensified

by perhaps the most innovative design feature,

hidden behind the train's sleek bodywork.

So, instead of traditional coiled mechanical Springs,

the aerotrain had a system of pneumatic air bladders.

Actually, if you can look up here, you can see them.

They're positioned around the corners of the carriage.

Initially hailed as revolutionary,

the train's air ride suspension system would,

in theory, isolate passengers

from the effects of vibration and body roll.

The train was intended to literally float

on a cushion of air.

The pneumatic system of the aerotrain

is set up with pneumatic bladders underneath...

Air bladders...

Similar to these right here,

the idea being the bladders and a control-box system

could adapt to the conditions of the train...

The weight, how many passengers were...

Giving a tunable ride.

The aerotrain's suspension system

was another engineering advancement with huge potential

that, unfortunately, was left unrealized.

Got a board on top of very similar bladders.

Now, this board, as we can see, with a little bit of motion,

creates quite a... Quite a vibrational ride.

The quality of the ride is gonna be similar

to the water in this cup.

So, what I'm gonna do is, I'm gonna apply

a little bit of force here,

and what we can see is a little amount of force

creates a lot of displacement, sloshing the water around,

meaning that the passengers in this particular carriage

are being shaken all over the place.

A very unpleasant ride.

A design fault which could have been easily rectified

by making the train cars heavier,

but at the expense of speed.

Now, what this does... By adding the weights,

it effectively stiffens the Springs

in the suspension system... The air Springs...

By increasing the internal pressure,

creating a tension in the bladder.

With a stiffer suspension and the added weight,

the same amount of force applied creates less shaking,

less displacement.

The result is a more comfortable ride

for the passengers in the carriage.

Even though it never went into production,

the aerotrain's place in automotive history

has inspired train engineering of the future.

Thanks to the development

of its innovative air suspension system,

today, passengers are able to travel in comfort

and faster than ever before.

Well, there's no doubt that this train did do

what it was supposed to do,

but, actually, it did something much harder...

It captured the imagination.

So much that, even 60 years later,

the aerotrain still lives on in miniature version,

appearing in theme parks around the country.

People all over still love this train.

It's a remarkable train in terms of its appearance.

And even though, ultimately, it wasn't successful,

I'm glad they tried.

But designing trains to run fast is just one of the challenges

facing engineers in the need for speed.

It's quite intense today because we have some unexpected event.

Laying the tracks for them is another.

He can move and hurt somebody, so it's an operation

that you have to carry out with concentration.

Across the world,

trains are reaching great distances at high speeds.

Thanks to technological advancements,

engineers are testing the limits in the need

to make the planet's railroads run faster

and more efficient than ever before.

But in order to travel fast,

a train is only as a good as its tracks.

Great Britain.

A nation that relies heavily on speed

to keep its vast rail network moving.

Completing nearly 4.7 million trips a day,

London's trains cover over 21,500 miles of track.

But keeping this huge infrastructure

in working condition

is an enormous-yet-vital challenge.

Historically, rail lines were inspected manually,