Original subtitles

This time on "Impossible engineering,"

extreme railroads.

Railroads of the water world.

Their unique challenges...

The majority of the surrounding area is swamp and bayou.

You really can't even see land on the other side.

And the ingenious solutions...

So this is it.

That's the solution the engineers found.

It's an incredible effort to do that.

Undoubtedly, this is the most challenging

engineering project ever to have been realized.

That make the impossible...

Possible.

It's difficult to imagine life before the railroads

when vast expanses of terrain

left some lands laying undiscovered.

Since the 19th century, engineers have taken on

some of the planet's harshest landscapes...

Building railroads to cross countries

and connect remote communities.

But there's one environment

that presents an almost impossible challenge.

Engineers have fought their hardest battles

to overcoming our water worlds.

Just have a look around.

Incredible terrain here. So many challenges.

The atmosphere is really moist and really salty.

Corrosion in certain areas is absolutely massive.

The difference of level... about 70 meters.

It needed some very special engineering process

to solve the problem.

And at the end of the 19th century,

it was one giant stretch of water in the U.S.

That would prove profoundly challenging for engineers.

Louisiana... it's a region that's characterized

by its wet, swampy geography.

In the late 1800s, engineers were challenged

to build a railway that could connect New York

and San Francisco with the trading port of New Orleans.

However, an imposing body of water stood in their way...

Lake Pontchartrain.

Today's a beautiful day, and the seas are flat calm,

but, uh, I've been out here with winds

over 50 miles per hour

and seas in excess of 8 feet.

Railroad engineer pat Weldon

has experienced the challenges of the lake firsthand.

The majority of the surrounding area

is swamp and bayou.

You know, you'll look across lake Pontchartrain,

and you really can't even see land on the other side.

To conquer this formidable body of water by train

requires a work of engineering on an equally grand scale.

The lake Pontchartrain trestle.

Stretching 5.8 miles long.

This super-sized concrete ballast deck bridge

is the longest railway crossing over water on the planet.

Originally built entirely from wood,

this record-breaking structure

was completed over 130 years ago.

Still standing strong against the elements today,

pat's making his way out on the water

to carry out some critical repairs

while his team is riding the rails

in a specially adapted truck.

All right. Here we go. Mr. Dave, are you ready?

All clear.

Overcoming the massive distance across the swampy lake,

the trestle grants the railroad direct access into New Orleans.

When you grasp the concept that we're covering

over 5 1/2 miles of lake with a bridge,

it's just an incredible feat.

And maintaining this link is vital.

Yeah, we'll start on the joints first

and get that knocked out.

While splitting the lake from shore to shore

solved the challenge for the railroad,

it creates another problem for boats.

Your vertical clearance

for the majority of the bridge is very low.

Most boats, even moderate-sized...

It will be difficult for them to pass

underneath the ballast deck.

Unloading station here.

To allow both water and train traffic

to travel the lake without issue,

the Norfolk Southern railroad

turned to an ingenious engineering solution.

Spanning 219 feet,

this remarkable piece of railroad infrastructure

is the key to the Pontchartrain trestle's success.

The brainchild of American engineer

William Donald Scherzer.

The rolling bascule is renowned

for its robust, low-maintenance design,

ideal for operating in the watery wilds of the lake.

This is a tough place to get into.

To make repairs is a difficult thing to do.

There's no other place on Norfolk Southern

or any other railroad, for that matter,

that really compares.

To get today's track maintenance work done,

the bascule's impressive engineering

needs to kick into gear.

We have machinery at the top of the bridge

that is powered by two electric drive motors.

There are two pinions,

and those pinions rotate across a rack system.

Essentially, what happens is it applies force

to open the bridge.

By harnessing the nearly 830-ton mass

of the counterweight

to assist the motors in lifting the span,

the bridge rolls back like a giant rocking horse.

This rolling action allows for

a much smoother transfer of load while the bridge operates.

With railroad operations now at a standstill,

the team needs to work fast.

How's it look, Jeb?

We had this... Uh, 2:00 P.M. looks good.

Good deal. Sounds good.

Facilitating the crossing

of up to 15 freight trains a day,

the bridge's heavy use results in wear and tear

to some of its key components.

For example, the miter rails.

These miter rails act as running rails for our train traffic.

They also allow the drawbridge to operate up and down

and for those rails to break

when the drawbridge is operated to the raised position.

Miter rails are composed

of two interconnecting pieces of track.

When the span opens,

the lift rail slides away from the stationary rail.

And when the bridge closes,

the two realign with millimeter precision.

Anytime that we have

a major crack or defect in the rail,

it either has to be repaired or it has to be slow ordered.

And a slow order is basically

a speed restriction that requires us

to reduce the operating speed of the train.

Today's repairs are critical, yet straightforward,

but this bridge has had to withstand

more than simple wear and tear in its lifetime.

The exposed location leaves it vulnerable

to the very worst weather that nature can muster.

This rail line is a vital link

to our gateway in New Orleans, Louisiana.

If a storm was to damage

or destroy any portion of this bridge,

it would have a serious impact on our operations.

It's a nightmare scenario

that the railroad experienced in 2005

as the southeast was ravaged by one of the worst storms

in American history... Hurricane Katrina.

The Pontchartrain railway bridge

actually lost 4.7 miles of its track and ballast section.

That track was washed off the bridge deck

and into the bottom of the lake.

Despite the unprecedented destruction

wrought by Katrina,

the railroad's maintenance teams fought back.

We used a total of nine barge-mounted cranes,

and we had a team of divers that worked with the cranes

to attach rigging to the track

and then pull it up and back onto the bridge deck.

16 days after the landfall

of one of the worst hurricanes in modern history,

Norfolk Southern was able to restore rail service

into New Orleans.

The amount of determination was nothing short of remarkable.

Since restoring service across the lake

in the wake of Katrina...

We get this bridge to the upright position.

You guys planning on taking it back down?

Yes, sir. That's correct.

I told them to bring it right back down.

Okay. Understood.

The Pontchartrain trestle

has continued to act as a vital link into New Orleans,

and today's repairs are keeping this railroad on track.

This is northbound train 198.

Every day, this record-breaking bridge

continues to allow the railroad

to conquer this vast body of water

and achieve the seemingly impossible.

This is an amazing engineering feat,

the construction of this bridge.

And to be able to be part of that and have some hand

in maintaining the safe operation of the railroad

is very gratifying.

While railroad engineers

strive to overcome our water worlds,

some of the most remarkable achievements

have been realized underwater.

The English channel,

stretching as wide as 150 miles across.

It's the dividing line that separates Great Britain

from continental Europe.

Packed with giant ships

and frequently struck by wild weather,

crossing this formidable body of water

can present a daunting challenge.

But in the 1980s,

railroad engineers from Britain and France

joined forces in an attempt to conquer the channel by rail.

Here we are, just to the east of Dover.

The English channel runs in the distance.

This would have seemed a virtually impossible task

at the time,

to create a fixed link between the two countries.

Civil engineer Dave Johnson

has been closely involved with the ambitious project

since its inception.

One of the options was to have a bridge going across.

They were talking about 5-kilometer-long spans,

which was massive.

But the idea of bridging the 18-plus-mile distance

between Folkestone and Calais was fatally flawed.

We have the busiest stretch of water

for shipping in the world,

so there would have been a risk during the construction

and afterwards that, at some time,

there could have been a collision

between a ship and the bridge supports.

In order to achieve their ambition

and avoid the dangers of the congested shipping lanes,

engineers reached a record-breaking solution...

The channel tunnel.

A railroad construction of epic proportions

carrying both passengers and freight

between Britain and France under the sea.

With the option to board from London...

And terminals at Folkestone for vehicles to drive on.

The channel tunnel has turned what was

a 90-minute, weather-dependent ferry trip

into a simple 35-minute ride on the rails.

It's easy to take these things for granted,

but every time I use it, you can't help wondering what

an amazing bit of infrastructure that we have here.

This rail network

carries 22 million passengers a year,

making what was once thought to be an impossible journey...

Possible.

Here we go. We're coming out in France now.

There we are.

But realizing this long-held dream

of connecting the two countries took a team of 13,000 people

more than five years to construct.

Massive logistics involved.

We're talking about three tunnels 50 kilometers in length,

of which 38 kilometers roughly lies underneath the sea.

This huge tunneling process

took place up to 245 feet below the sea bed,

working off-shore from both countries.

Large tunnel-boring machines,

which have a large rotating head,

with sharp, cutting teeth to get through the ground,

slowly started to work towards one another across the channel.

And eventually, on the 1st of December, 1990,

the two service tunnels met in the middle for a celebration.

Four years later, having laid the track

and installed power to the lines,

the channel tunnel opened in 1994,

crowning it the longest undersea railroad tunnel on the planet.

Conquering this most challenging of environments

was an incredible feat,

but engineers still have to fight the water world

every single day.

John Keefe is a member of the team involved

in this mega project.

In engineering terms,

it compares to things like the Panama canal,

Suez canal, the hoover dam.

It's of the order of magnitude that has been recognized

as one of the seven wonders of the modern world.

Undoubtedly, this is the most challenging engineering project

ever to have been realized.

Around 400 trains pass through the tunnel each day,

an operation that is monitored behind the scenes

at channel tunnel HQ.

This is a bit of an exclusive area.

It's a bit of a secret.

This room is our railway control center.

It's the heart of the whole of the channel tunnel.

We basically run everything from here.

That includes all of the time tabling

for the railway movements.

A time table that the maintenance teams

crucially have to work around.

Every week, two nights of maintenance are scheduled

on Saturday and Sunday night.

We'll take a section of the tunnel out of service,

and the railway system continues to operate around them.

Tasked with carrying out this weekend's vital work

is lead engineer Mark Cornwall.

Now we got about 15 kilometers to the location,

where our train is, to start work.

Running an electrically powered railroad

in a damp, undersea environment

presents constantly evolving challenges.

No one's ever maintained anything like this before.

We've come up against lots of different complications.

The atmosphere in certain areas is really moist and really salty

because you get a lot of seepage from the sea bed.

The corrosion in certain areas is absolutely massive.

We have a massive program in place

of changing out 3 kilometers of the tunnel.

Tonight, Mark's team is carrying out

a routine inspection of the contact wires

that run along the top of the tunnel.

But there's a more pressing element to the job.

Upgrading a vital component

in the system that delivers power to the trains,

Mark and the team must work safe and fast

to finish the job in time for the morning passengers

to catch their trains

without compromising the electric rail system.

Mark Cornwall and his team

have been tasked with upgrading a part of the electrical system

powering the channel tunnel trains,

and the clock is ticking.

What we're doing tonight is we're changing out

the registration parts and feeder parts.

We're changing them from porcelain to synthetic.

So let's make a start.

Installing the new synthetic insulators

will reduce the risk of the damp environment

causing a power failure

that could bring the railroad to a halt.

On this shift tonight, we're gonna try to change out

most probably 30 insulators.

When we leave here, the trains must be able

to run first thing in the morning.

As you can see, it's a long procedure

just to do one location.

But six hours later, it's job well done,

and the tunnel can be put back into operation once again.

Working in this unique atmosphere

is all part of an ongoing, invisible battle

to keep this record-breaking railroad on track.

I love my job.

I've been here 26 years now,

and this will be where I retire, I hope.

Making its epic journey under the sea...

There's a lot of things I'm quite proud of,

the sheer scale of it.

It's the longest undersea tunnel in the world.

And achieving the seemingly impossible every day.

The channel tunnel is the biggest thing

you'll ever see in my lifetime.

It just don't get any bigger than this.

In 20 years or 50 years or 100 years,

there will be something bigger and better,

but, for now, this is it.

While some railroads are built

to transport trains underwater,

this engineering feat was built to transport ships across land.

The Panama canal is one of the planet's

most significant trade routes.

Stretching for 50 miles,

it cuts through the heart of the country,

connecting the Atlantic ocean in the north

with the pacific ocean in the south...

And saving 8,000 nautical miles per journey for ships

that pass through it instead of the alternative

and risky route around cape horn.

Senior lock master Emilio Liao Lee

is at the Miraflores locks

at the pacific entrance to the canal,

the unlikely setting for a feat of railroad engineering.

There is an unbelievably tiny 23-inch gap

between the walls of the locks

and the sides of the largest vessels.

And any damage to the locks

could have a catastrophic effect on world trade.

In the early 1900s,

the task of solving the problem of guiding ships through

fell to the canal project's

electrical and mechanical engineer, Edward Schildhauer.

Schildhauer would need to design a system

that would have enough power to control the enormous weight

of the fully loaded ships at they change elevation.

The solution, incredibly, was a railroad,

and a unique locomotive known as the Panama mule.

Weighing 47 tons each, these workhorses run in pairs

to keep the vessels centrally aligned.

It was a solution that was so comprehensive

that it's still in use today.

Running along rack rails parallel to the canal,

a gear on the locomotives meshes with the rail,

giving them enough traction to surmount gradients up to 44%.

Mule driver Roberto Augusto Thompson

is assisting the lockage today.

A small rowboat then passes the cables

to be attached to the ship,

and then back to land, where the railroad steps in

to take its fundamental role.

Once the gates have closed,

water rushes in to elevate the ship.

During the lockage, ships transit under their own power.

But for the next eight minutes,

the mules have to ascend the rails

and move in unison with the vessel

to maintain enough lateral tension

in the ropes to keep it centered.

Each locomotive has two 290-horsepower traction units

and is powered by electricity fed through the tracks.

For large ships, up to eight mules work together,

each with a driver sitting in a central cabin

keeping tight control.

But power wasn't the only challenge to overcome.

These massive ships left the mules at risk

of being dragged off course.

It would take some innovative engineering

to keep these mighty workhorses and megaships on track.

In the Panama canal, these mules are tasked

with guiding mega cargo ships safely through the lock.

But what keeps the little locomotives

from being dragged off course by the sheer pull of their charges?

This army of 100 unique locomotives

works continuously throughout the day

with the help of a turntable

moving with the changing direction of ships

in and out of the pacific,

making it possible for 14,500 ships

to pass through the Panama canal each year,

all thanks to Schildhauer's ingenious railroad.

Overcoming heights in a water world requires locks,

but sometimes, a more radical railroad solution is necessary.

It was one such challenge facing engineers here

in the famously flat landscape of central Belgium.

In the 1960s, there was a need to speed up

the vital flow of trade

along a section of the Charleroi to Brussels canal,

a problem waterways expert Yvon Loyaerts knows well.

This time consuming, about two-and-a-half days

for the whole trip from here to about 20 kilometers further.

Slowing down the cargo

was a steeply sloping section of the canal...

A cumbersome stretch of 14 locks,

taking a day to move through.

The difference of level... about 70 meters.

In fact, it needed some very special engineering process

to solve the problem.

Incredibly, it was a radical feat

of railroad engineering that provided the answer.

Engineers have to be creative.

And so we can mix technologies. Why not?

What they dreamt up

was the monumental Ronqui?res inclined plane.

The world's longest sloping lock...

Almost a mile long...

And 223 feet high.

Boats take to the rails

aboard a pair of huge water-filled tanks,

conquering the incline

and reducing what was a seven-hour trip

to just 40 minutes.

The purpose of this construction

was mainly to help us

gaining some time in terms of using the locks.

As before, we had many locks to use.

It made the traffic so slow.

Today, guide Arnaud Ketels

is riding the revolutionary sloping lock

as it helps yet another vessel pass through the incline.

So, at this moment, we are bringing a merchant ship

from the upstream to the downstream

down a slope of 5%.

The system works in a similar way

to toy boats in a bathtub...

only on a much larger scale.

During a normal week from Monday to Friday,

we have between 10 and 20 boats a day.

The fact that we can carry such boats...

1,350 tons of merchandise...

It allows us to spare 70,000 lorries from the world.

Each giant tank, or caisson,

contains over 105,000 cubic feet of water.

In a caisson,

that's 91 meters long

and 12 meters large.

And their movement is driven

by a rail-mounted counterweight system.

We have two railways... One for the caisson itself

and one for the counterweights under the caisson.

This ingenious inclined plane

can transport each tank, plus the fully loaded barges,

over a world-record distance.

There are other sloping locks in the world,

but a sloping lock of 1.4 kilometers...

It's the first inclined plane of this size.

To make this impossible concept a reality,

engineers had to get creative

and find some groundbreaking solutions.

The Ronqui?res inclined plane

is the longest sloping lock in the world,

and it revolutionized the flow of cargo in central Belgium.

Yet the mechanism behind this mode of transport

is brilliantly simple.

First, the barge enters the tank through a lock gate

that shuts behind it, trapping water inside.

An electric motor then hauls a cable,

moving the tank in one direction

and a counterweight in the other.

At the end of the incline, a second lock gate opens,

and the barge continues on its journey.

Yvon is watching the whole impressive operation unfold

from a unique perspective.

The tank is now going down.

You see all the running wheels going on the track,

and, of course, naturally, when the tank is going down,

is running down, a counterweight will go up.

As the 5,730-ton weight climbs the slope,

the giant tank of water carrying the barge

descends at a speed of 3.9 feet per second.

It is, in fact, a system as for a cable car.

The only difference is that it will be bigger, of course.

It's a large difference, in fact.

Driven by six electric motors,

two winches haul the eight massive cables

attached to each tank and its counterweight

over the 223-foot height difference.

There are two systems in parallel.

Each system is 16 cables,

more or less 1.5 kilometers as length.

Thus it means a little less than 50 kilometers' length,

with all the cables.

When it was conceived, many thought constructing

the epic Ronqui?res inclined plane would be impossible,

but when it opened in 1968, after six years of construction,

this railroad transformed Belgium's canals.

We had to find

some very new solutions to make it work,

and, luckily, they were good solutions

because 50 years afterwards, it still works,

and it's still in use and on a very efficient manner.

And thanks to this incredible piece of engineering,

today yet another boatload of cargo

has saved hours on its journey.

It's an amazing piece of engineering.

In Belgium, the Ronqui?res rail system

helps the shipping industry stay afloat.

In Switzerland, it's the tourism industry

engineers are looking to keep on track.

Local Mark Von Weissenfluh is en route

to one alpine setting

that visitors desperately wanted to reach.

Tourists from all over the world came to visit

the area of the Bernese Oberland and the lake Brienz.

And, of course, they also wanted to see the Giessbach cascades.

14 cascades going downhill into the lake.

Thanks to its remote, almost island-like location,

the only way to access this beautiful spot was by boat,

but even then, an arduous hike up a 328-foot incline

and across the area's iconic waterfalls

stood between visitors and the opulent hotel above.

So this is it.

That's the solution the engineers did find.

They created the Giessbach funicular.

This historic funicular opened in 1879,

turning what was once an impossible journey

into an awe-inspiring, 1,130-foot-long ride by rail.

This is one of my most

spectacular journeys up here.

Every time you drive up this hill,

it's like being 140 years thrown back in time.

It's just very impressive.

Where a steam locomotive of the time

lost traction on gradients beyond 5%,

this traverses a mighty 28% gradient,

overcoming the fast-flowing falls in the process.

But to work around this watery landscape

posed an enormous challenge,

not least how to power the funicular.

Tasked with the job

was Swiss engineer Carl Roman Abt.

In a funicular system,

one car goes up while another goes down,

the weight of the two carriages counterbalancing each other.

But additional power is needed to exceed

the counterbalance and create motion.

Abt needed to find an impossible solution

to power this massive system in the heart of the Swiss alps,

but he didn't have to look far to find the answer.

Swiss engineer Carl Abt

needed to find a way to power

his exquisite counterbalanced funicular system

in the remote alpine setting of Giessbach.

Inspired by the spectacular water world around him,

Abt used water from the falls

to weight the upper carriage and induce motion.

The water flows over to the tank,

which was underneath the cabin,

so the car was filled with water,

and the extra power has been here to generate

the pulling up of the second wagon

down by the lake and get the passengers up.

Very easy, very simple.

Having found a solution to power his funicular,

Abt now faced the task

of building the track that would carry it.

Early designs featured two tracks side by side,

but space and budget

would impose impossible restrictions here.

So, looking at that hill,

we can see the challenge behind it.

The cars have to conquer that steep hill,

and it was only budget for one track.

But the cable car, of course,

it has two cars, so how to do that?

There had to be a genius of an engineer to come up with an idea

to create a solution with one track and two cars.

Abt's space- and cost-saving solution

was to design a single-track funicular

with an ingenious passing loop, allowing two trains

to travel up and down the mountain simultaneously.

So, it's called the Abt switch.

The cars can cross halfway up the hill,

and we have just one track

all the way up the hill from the bottom.

Traditional train wheels

have a flange on the inside to keep them on the rails.

Abt designed his wheels so that both edges

were flanged on one side of the carriage,

and on the other side, the wheels are simply rounded.

The flanged side follows an uninterrupted guidance rail.

As the carriage approaches the Abt switch,

the rail diverts it to the outer edge,

allowing the two carriages to pass each other.

That's the first time in the world

it has been realized on a funicular.

So when you look around

and you see that incredible terrain here,

it was just logical

to create that solution with only one track.

Abt's single-track solution was groundbreaking,

finally solving the problem of how to transport people

up and through this watery wilderness.

And while the Abt switch

has gone on to become a fundamental part

of today's cutting-edge funiculars,

this historic landmark has stood the test of time.

Just imagine in 1879

when they, for the first time,

drove up that hill

in this spectacular, comfortable transportation.

It's so unique.

Since railways began,

water has given them a mighty challenge...

Inspiring solutions that cross great divides...

This is an amazing engineering feat.

To be able to be part of that is very gratifying.

Raising engineering to a higher level...

It's such a beautiful piece of engineering,

so this is almost art.

To create extreme railroads.

This channel tunnel is the first time

we've had a connection between Europe and the U.K.

Since the ice age.

It is of worldwide importance.

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