Disaster Autopsy (2024) s01e01 Episode Script

1
[Narrator] In a
high-rise building.
-There was no warning.
[Narrator] At sea.
-Innocent people died.
[Narrator] In a train.
-Everything was on fire.
Everything was burning.
[Narrator] Disasters can begin
with the smallest things.
-Changing the opening
hours of a restaurant.
-The bad glue job.
-A paperwork error.
[Narrator]
Now, combining the
latest research with every
available source of evidence,
experts will forensically
analyze three disasters
down to each tiny detail.
-You've really got to
think outside the box.
-You have to work your
way back and understand
each link in the chain.
[explosion]
[Narrator] State-of-the-art
graphics reveal every critical
detail at every
critical moment.
-This whole disaster
could have been averted.
[Narrator]
We can dissect them.
Get inside.
Or underneath.
Freeze time.
And even reverse it.
To conduct a complete
Disaster autopsy.
Houston, Texas.
February 1st, 2003,
Mission Control.
Space shuttle Columbia is
returning to Earth after
a flawless 16-day mission.
-Things seem to be going well,
what they call nominal.
[Narrator] 15 minutes into
re-entry, mission control
radios Shuttle Commander
Rick Husband.
[mission control] And Columbia,
Houston, we see your
tire pressure messages and
we did not copy your last.
This is instrumentation max.
[overlapping radio chatter]
[astronaut] Roger.
[Narrator] Mission control
never hear from Columbia again.
People on the ground realize
something has gone
terribly wrong.
[mission control]
Columbia, Houston comm check.
Columbia, Houston
UHF comm check.
[Margaret Harris] You see
these streaks of light going
across the sky behind
the shuttle and, you know,
something awful has happened.
[Narrator] All seven
astronauts are lost.
-It was clear that no one
walked away from that.
No one survived that.
[Narrator] Now, using
evidence from the wreckage,
NASA telemetry, and
scientific analysis,
we will reconstruct
the entire disaster.
What brings down
space shuttle Columbia?
More than 84,000 pieces
of debris are recovered
across Louisiana and Texas.
Including one
miraculous discovery.
A data recorder from
Columbia is found
almost completely intact.
It holds vital readings
from sensors all over the
spacecraft before and
during the disaster.
We also have the data
transmitted from Columbia
back to Earth.
-NASA has lots and lots of
telemetry from Columbia.
In fact, mission control could
see far more about what was
going on Columbia
than the flight crew could.
[Narrator] This data tells
us that immediately before
entering Earth's atmosphere,
Columbia is in the correct
40-degree nose-up orientation.
But just minutes later anomalies
appear in the flight data.
-The spacecraft is being
pulled to the left.
So, the onboard computer is
using the control systems
on the wings to try
and pull it back.
[Narrator] This is alarming.
It's critical the shuttle
continues pointing nose forward,
because it is still traveling
at over 18,000 miles per hour.
[Peter Hollingsworth] If you're
not flying straight ahead,
if you're tilted the side,
the forces are so great,
the spacecraft
will break apart.
[Narrator] But examination
of the flight data
reveals a rapidly
deteriorating situation.
-Not only is the aircraft
turning to the left,
but it's rolling to the left,
indicating the left
wing is losing lift.
[Narrator] The control
surfaces on the wing are
struggling to keep the
shuttle pointing straight.
-About 15 minutes
after re-entry the
flight computer fires the RCS.
[Narrator] The RCS is a system
of tiny rockets designed to
orientate the shuttle.
[Margaret Harris] At
this point, you've got two
different systems trying to
control the left yaw,
you've got the RCS and you've
got the aileron trim.
But despite their best efforts,
the drag is still increasing,
the left yaw is
still increasing.
the problem, whatever it is,
is getting worse.
[Narrator] Returning to
space is not an option.
-The shuttle is effectively
an unpowered, massive glider
and it's only going one way.
[Margaret Harris] Eyewitnesses
on the ground start to see
pieces of debris
coming off the shuttle.
[Maggie Aderin-Pocock] What
we think happened is that the
nose went up,
the spacecraft goes
into a flat spin
and the aerodynamic forces
working on the spacecraft,
which is still traveling
at 10,000 miles per hour,
the spacecraft just
gets ripped to shreds.
[Narrator] Why do they
lose control of the shuttle?
The data shows Columbia is
turning and rolling to the left.
[Sophie Harker] The only thing
that would really cause that
is if the wing was
changing shape mid-flight.
[Narrator] How can a
solid wing change shape?
-Being NASA, they have
sensors everywhere.
They measure temperature,
load, other conditions
on the spacecraft.
[Narrator] The sensors inside
the wing transmit vital clues.
-About four and a half minutes
after the re-entry interface,
four of those temperature
sensors started sending
some very strange responses.
One of those sensors started,
that was expected to be around
30 degrees Fahrenheit was
showing 65 degrees Fahrenheit,
which is still high, but okay.
Then a second sensor that
was expected to be around
20 degrees Fahrenheit started
showing 450 Fahrenheit,
which is a very big anomaly.
[Narrator] As the shuttle
descent continues there are
more and more data anomalies.
-The sensors on the landing gear
suddenly start going haywire.
The landing gear is up.
It's down.
It's locked.
It's not locked.
-All these different sensors
start failing simultaneously,
but they're not connected.
So, what's happening?
[Narrator] The only common
factor is that they are all
inside the left wing.
Temperature sensors suggests the
wing interior is getting hot,
hot enough to
damage the other sensors.
-The question is, where
is the heat coming from?
[Narrator] During re-entry,
the shuttle slows from around
18,000 miles an hour to just
a couple of hundred
miles an hour.
-All spacecraft use
what's called Aerobraking.
They use the drag generated
by entering the atmosphere
to slow them down.
[Sophie Harker] The amount
of heat that that generates
actually means the air
itself starts to separate.
Particles start to separate
and it turns into something
we call plasma.
[Narrator] The glowing
white-hot plasma surrounding
the shuttle on re-entry
can reach temperatures
of 5,000 degrees Fahrenheit.
[Margaret Harris] If all these
sensors are failing at once,
the most likely culprit is
that the superheated air
generated during
re-entry is actually
getting inside the wing.
[Narrator] That would
inflict catastrophic damage.
-With this plasma
inside the wing,
things are just distorting
and it explains many of the
strange readings
that we're getting.
[Narrator] But the parts of
Columbia in contact with the
plasma should be protected by
ceramic tiles on the underside
and reinforced carbon-carbon
panels, known as RCC
on the wings' leading edge.
This is the
spacecraft's heat shield.
[Peter Hollingsworth] There's
only one way the white-hot
plasma can get in the wing and
that's if there's a hole in it.
[Narrator] Columbia is
unprotected from
the super-hot plasma.
[Margaret Harris] It's eating up
the shuttle one chunk at a time.
-How did a hole get punched
into the left wing of Columbia?
[Narrator] Analysis of the
pattern of sensor anomalies
points to a hole on the thin
leading edge of the wing,
on RCC panel eight.
-It looks as if the shuttle
flew into something.
[Narrator] Could the shuttle
have flown into debris in orbit?
-It's a possibility because
there's around 8,000 tons of
human-made junk circling the
planet at any one time.
[Narrator] Even a microscopic
piece of debris can be lethal.
-In 2016, a window on the
International Space Station
had a seven-millimeter gouge
created by a paint chip that was
less than a few thousandths
of a millimeters wide.
-Even if it's very small,
it's very dangerous
because it's going so fast.
[Narrator] Given the hole is
on the front of the wing,
it makes sense that the
shuttle might have flown
into a piece of debris.
Except that's not how
things work in space.
[Peter Hollingsworth] Because
in space, there's no air.
You can fly in
any orientation.
So instead of flying forward
like an aircraft, you often
are oriented differently, so
it's very rarely that you're
flying in that kind
of normal position.
[Narrator] So, there is no
reason the hole should be
on the thin front of the
wing rather than elsewhere.
[Peter Hollingsworth] Having
that hole in the leading edge
indicates that it's less likely
to be from space debris.
It's more likely that it
occurred on launch when
the shuttle is flying in that
facing forward orientation.
[Narrator] Was Columbia's fate
sealed 16 days earlier
before it even reached space?
[Narrator] Launch day for
Columbia's mission, STS-107,
is January 16th.
[mission control] Ten
-The space shuttle is actually
made of three main components,
the orbiter, the main fuel tank,
and then the booster
rockets on the side.
[Narrator] At 10:39 a.m.
Columbia lifts off.
[Margaret Harris] Okay, so
we've kind of narrowed it down
to something that must
have happened at launch.
[Narrator] NASA uses powerful
telephoto cameras to
track every launch.
This footage reveals
one critical moment.
-So 81 seconds after launch,
an object falls down from
high up of the space
shuttle's configuration and
hits the wing, RCC Panel eight,
and that is exactly where we
think the problem started.
[Narrator] The location of
this object suggests it's a
piece of lightweight
insulating foam from the
outside of the
external fuel tank.
[Maggie Aderin-Pocock]
Analysis of the footage shows
that the piece that breaks off
is 21 to 27 inches long
and 12 to 18 inches wide.
It's thought to
weigh about 1.7 pounds,
which is quite light.
[Narrator] Could such a tiny
chunk of foam really
bring down the
billion-dollar spaceship?
[Maggie Aderin-Pocock] It's
not the mass, it's the speed
at which it's traveling.
Double the speed, four
times the impact energy.
-We can estimate that
the speed of that foam,
when it impacted the wing
was somewhere between
416 and 573 miles per hour.
That is a hell of a speed.
That is fast.
That is like the
speed of a jetliner.
[Narrator] Is that enough for
such a light piece of foam to
fatally damage the spacecraft?
NASA records show that after
the loss of Columbia,
they test this theory.
-They took an old panel
from another shuttle
and shot foam at that
panel at the expected speeds.
[Narrator] The
results are shocking.
[firing]
[Maggie Aderin-Pocock] I think
we can say pretty unequivocally
that the foam strike on the
leading edge of that left wing
brought down the shuttle.
[Narrator] Which
leaves just one question.
Why did the foam fall off
the tank in the first place?
Rewinding the critical moment,
this foam appears to fall from
the attachment between
the tank and the shuttle,
known as the bipod.
Critically, the foam
here is applied by hand.
[Sophie Harker] The problem
with hand spraying is that you
end up with these gaps and
voids right between the foam
and the tank that you just
can't avoid and they're tiny
but they're there.
[Narrator] Could these voids
cause the foam to detach?
Before the tank is filled,
NASA protocols dictate blowing
any residual gases from
it using inert nitrogen.
[Sophie Harker] The external
fuel tanks carry about half a
million gallons of liquid
oxygen and liquid hydrogen and
those things need to be
stored cryogenically,
so they need to be
stored very, very cold.
[Narrator] Any remaining
nitrogen that comes into
contact with these ultra-low
temperatures condenses into
a liquid and this can flow into
the voids in the
insulating foam.
So, at launch, some voids may
be filled with liquid nitrogen.
[Margaret Harris] The problem
is it doesn't stay liquid.
As the shuttle launches there's
all sorts of heat sources that
cause it to turn from
a liquid into a gas,
and a gas takes up much
more space than a liquid,
and as it expands,
it pops the foam off.
[Narrator] These tiny pockets
of nitrogen are just one link
in a deadly chain of
events that ends in disaster.
[Margaret Harris]
Columbia's mission, STS 107,
leaves the launch pad
on January 16th at 10:39.
[Maggie Aderin-Pocock]
At 81 seconds,
a small piece of foam is
dislodged from the tank
due to the expansion
of the liquid nitrogen.
[Narrator] The foam strikes
the leading-edge RCC panel eight
on the left wing and
punches a hole in it.
-Columbia's fate is now sealed.
[Maggie Aderin-Pocock] Upon
re-entry as soon as the air
starts to heat up around the
spacecraft, the plasma gets in
through that hole and
starts wreaking havoc
within that left wing.
The increasing drag on
that left wing overwhelms
the control system.
The spacecraft goes
into a flat spin and at
10,000 miles per hour
it's torn to shreds.
[Narrator] All seven
astronauts are killed.
Following the Columbia disaster,
NASA removes the
insulating foam in the
area around the bipod strut.
After Columbia, no
shuttle is ever lost again.
On July 21st, 2011,
the shuttle program
completes its final flight.
Columbia is brought down
by a flaw on its exterior.
But you don't have to be in a
spaceship for that to happen.
England, London.
Royal Borough of Kensington.
Grenfell tower.
-Grenfell Tower is a 24-story,
221 feet high,
residential building
that had been part of
the London skyline
since the 1970s.
[Narrator] At 1:00 a.m. on
Wednesday 14th June 2017,
a small fire breaks out in
one of the 129 apartments.
[Margaret Harris] What starts
out as a small, containable
blaze rapidly escalates
into something that's far more
dangerous and far more deadly.
[Narrator] The fire spreads
quickly across the whole tower.
-To see the fire spread,
it's just incredible.
I've never seen anything
like that before in my life.
[Narrator 297
people are inside.
-People are trapped
in their homes.
There's no way out and
they're absolutely desperate.
[Narrator] It takes 24 hours
to extinguish the inferno.
Almost the entire
building is gutted.
72 people,
including 18 children,
are killed.
It is the UK's deadliest
peacetime residential fire
for 800 years.
Now using all the
available data,
we will digitally
replay the disaster,
to analyze the chain of the
events and answer one question.
-How could a small
apartment fire result in
such an enormous catastrophe?
[Narrator] The first thing to
establish is a timeline of the
Grenfell Tower disaster.
-So how did this fire start?
Well, in this case,
we've actually got a
fairly definitive answer.
Just before 1:00 a.m., the
London Fire Brigade logged a
call from the
resident in Flat 16,
saying his fridge
freezer was on fire.
[Narrator] Flat 16, where
the fire breaks out,
is on the 4th floor,
on the east
side of the building.
Photographic evidence suggests
the most likely source of the
fire is a fridge freezer.
But how does a relatively
small electrical fire
escape the apartment?
-The windows in Flat 16, like
elsewhere on Grenfell Tower,
are made of UPVC.
[Narrator] UPVC is a durable
rigid plastic material with
one obvious flaw.
-UPVC isn't especially
heat resistant.
So, it's very likely that
the heat from the fire in the
kitchen in Flat 16 is
more than enough to make
the windows start to
deform and melt.
[Narrator] This is backed up
by the witness statement of
a tower resident.
-He says that he initially
saw flames and smoke
behind the window.
But then the whole
thing just fell out.
[Narrator] Once the fire
escapes the flat,
video evidence shows that
it spreads rapidly,
reaching the top of
the building by 1:26 a.m.
[Andrew Steele] Two hours
after the fire service were
first called, almost half
of the flats are ablaze,
and by 4:30, the whole
building's on fire.
[Narrator] How can a fire
take hold on the outside of
a concrete building?
Video evidence of the
disaster holds vital clues.
[Sunday Popo-Ola] When this
fire started, within minutes
you can see droplets of fire
materials and that was coming
right to the ground floor.
And as the fire spread
to the upper floor,
you see more and more
of this material dropping down.
[Narrator] But this material
is not the UPVC of the
window frames, it's a
different plastic altogether,
polyethylene.
What is the source
of this plastic?
[Andrew Steele] Comparing
photographs of the building
from when it was built to
photographs taken in the
few weeks before the fire,
you can see it just looks
completely different.
The entire exterior of
the building has changed.
[Narrator] Maintenance records
for the building show the
tower undergoes an
£8.6 million refurbishment
just over a year
before the fire.
The work includes
new exterior cladding.
-Part of the reason for this
refurbishment was to improve
the thermal insulation
of the building,
keep things warmer
for the residents.
But it was also designed to
update the appearance from
this 1970s brutalist aesthetic
to something more fitting
for the modern era.
[Narrator] Examining the
cladding in more detail,
shows that it is made up
of multiple layers.
The first layer is
plastic insulation called
polyisocyanurate, or PIR.
It is attached to the exterior
of the existing building.
-Next to that, there's an air
gap about two inches across
and then there's this
sandwich of what's called
ACM, aluminum
composite material.
There's a layer of aluminum.
There's a layer of
polyethylene in the middle
and then there's another
layer of aluminum.
[Narrator] The polyethylene in
these cladding panels is the
only possible source of the
burning, dripping material.
-That's incredibly serious
because the whole building
is literally
covered in these things.
[Narrator] This explains
how the outside of a concrete
building is able
to start burning.
It takes little more than an
hour for the entire east side
to catch fire.
How can the fire
spread so rapidly?
The cladding on the
Grenfell Tower is attached using
what is known as the
"cassette system,"
and evidence has emerged
about the cassette cladding
used on Grenfell Tower
that reveals
something shocking.
-When the company that made
them tested them in 2005,
the performance of the
cassette system was so poor
it just completely
burst into flames.
[Narrator] The manufacturers
later said they thought that
this was just a
rogue test result.
So how does using the
cassette installation
increase flammability?
-It's called a cassette system
because it's folded into
a sort of C shape,
a bit like the old liners
in a cassette tape.
[Andrew Steele] This
method of attachment creates a
series of channels
between the cladding itself and
the insulation foam
and that means in case of fire,
you can get something
called the "chimney" or
"stack effect" taking hold.
-Hot gases, which are less
dense than cold ones,
rise up in a
sort of chimney effect
between the building
and the cladding.
[Andrew Steele] Effectively
the fire breaks out between
the cladding and the
building and that creates
another problem, which is that
exterior cladding is essentially
protecting the fire from
the firefighter's water.
[Narrator] Driven by
the chimney effect,
the fire spreads rapidly
up the side of the building.
But in less than an hour
it begins spreading
around the building as well.
How does the
fire move sideways?
[Narrator]
The Grenfell Tower fire
begins on the
building's east face,
but surprisingly it
rapidly spreads to the
north, south, and west sides.
-The first clue is the fire
on the very top of the building.
[Narrator] This is
known as the crown.
-We can see from video of this
fire that when it reaches
the crown, it hasn't
got anywhere else to go
in the upwards direction.
So, it starts to
spread around the tower.
[Narrator] The crown of
the tower is covered in
the same ACM panels.
-And that gives an almost
continuous path for
the fire to spread.
[Narrator] Thermal images from
a police helicopter show that
the burning crown ignites
cladding on the other faces
of the tower.
[Margaret Harris] There's
actually a waterfall of
burning material cascading
off the upper floors of the
building, off the crown.
[Andrew Steele] You've
got these flaming globs of
polyethylene falling down the
side of the building,
setting fires lower down,
which can then travel up the
face of the building again.
[Narrator] This explains how the
tower ends up engulfed in flame.
But this escalating disaster
plays out over several hours.
Why don't more
people manage to escape?
According to
eyewitness statements,
many remain in place
because that's what
they've been told to do.
[Margaret Harris] So,
Grenfell Tower, like a lot of
buildings of this type,
has a stay-put policy and
what this means is that
residents in the case of
some sort of emergency are
not advised to
leave the building.
[Sascha Auerbach] The reason
residents are advised to
shelter in place is because
each flat in the building,
each apartment in the building
is a discrete concrete box
that is kept separate
from the others,
specifically for the purpose
of fire prevention.
[Narrator] The entire policy
is built around the original
design of the building in
non-flammable concrete.
[Margaret Harris] The
problem is that by the time
this fire starts,
Grenfell is wrapped
in this flammable cladding and
it's nothing like
concrete anymore.
[Narrator] When the cladding
is fitted, the stay-put policy
is not reviewed.
By the time it is
revoked at 2:47 a.m.
so much of the
building is ablaze,
that most people still
in the tower are trapped.
Just one obvious
question remains;
how does Grenfell end
up clad in material
that is intensely combustible?
[Sascha Auerbach] If you look at
the original planning document
from 2012 for the cladding
that was going to be
added to Grenfell,
it was not aluminum with
a polyethylene core.
It was meant to be zinc with
a non-flammable core and this
was the design approved by
the residents of the tower.
[Narrator] An updated planning
application, submitted in 2014
is the first evidence of a
change to the cladding type.
[Andrew Steele] And we can see
from correspondence between
Kensington and Chelsea Council
and the contractors
why this decision was made.
The correspondence lists
requested financial savings
to decrease the overall
cost of the refurbishment.
[Narrator] This includes
£290,000 that would be saved
by fitting aluminum cladding
instead of zinc cladding.
There is nothing in these
papers to suggest that they
are aware this
will impact safety.
But the consequence
is that it does.
Ultimately, that decision
costs 72 people their lives.
[Margaret Harris] So we know
how this disaster unfolds.
It all begins with an attempt
to reduce costs by replacing
one type of
cladding for another.
-On June the 14th, 2017, just
a few minutes before 1:00 a.m.,
a call is made to the
London Fire Brigade.
The caller alerts them that
the fridge freezer in his
fourth-floor flat is on fire.
[Narrator] The fire brigade
arrives minutes later.
[Sascha Auerbach] But the fire
has started to expand rapidly.
The UPVC windows of the
apartment have fallen out
and the fire has now
escaped its initial location.
[Narrator] The flames
set light to the flammable
cladding on the
outside of the building.
-Thanks to the
arrangement of the panels,
which creates
this chimney effect.
The fire races up this
side of the building.
[Narrator] Once it
reaches the roof,
the fire moves sideways.
[Andrew Steele] The flames
spread laterally
around the crown,
dripping burning polyethylene
onto the rest of the
building and starting new fires.
[Narrator] The obsolete
stay-put policy means
many residents remain
in their apartments.
By the time the fire
is under control,
72 people have lost their lives.
Many more are
seriously injured.
[Sascha Auerbach] Immediately
in the wake of the tragedy,
both the bereaving families
and people across the country
demand an explanation.
The ramifications for the
Grenfell Tower fire are
ongoing and don't look to
be resolved any time soon.
[Andrew Steele] After the
disaster, there was a scramble
to identify other
high-rise buildings
with this kind of cladding,
and it turned out there
were around 500 of them.
[Narrator] The work to replace
this cladding is ongoing.
[Margaret Harris] So far, more
than 900 people, survivors,
bereaved people from the tower
disaster have received
£150 million in compensation
from the civil courts.
[Narrator] Despite the scale
of the disaster, so far,
there have been no
criminal charges.
The Grenfell tragedy
took hours to play out.
But disaster can
also strike in seconds.
Eschede, Germany.
A sleepy town in the
district of Celle.
[Andrew Steele] It's June 1998
and a high-speed train is
zooming round the gently
curved section of track just
outside of town and
this is a popular service.
Families, business people,
all trying to get to their
destination as
fast as possible.
[Narrator] The high-speed
train is the pride of the
German railways.
As it approaches Eschede
it is traveling at
125 miles an hour.
[Maggie Aderin-Pocock] Still
going flat out, the train
comes off the tracks and
smashes into a bridge.
[Narrator]
101 people are killed.
88 more are seriously injured.
It is the worst high-speed
train crash in history.
Now, combining all the
available evidence
with cutting-edge
digital technology,
we will recreate
the disaster and
piece together the
deadly chain of events
leading up to it,
to answer the question:
What causes this catastrophe?
[Narrator] The disaster at
Eschede begins as a completely
routine train journey.
[Andrew Steele] The train
in question is ICE 884.
It left Munich on the morning
of the 3rd and was heading to
Hamburg, a journey
of about 6 hours.
-The ICE 884
has 12 coaches,
including a passenger coach,
a restaurant, a service coach,
and then a locomotive
on each end.
[Narrator] No footage exists
of the accident happening,
but careful examination of
the photographic evidence
helps create a
disaster timeline.
-Immediately after the accident,
the front of the train,
the locomotive and the first
two carriages come to a stop,
a fair way down the track and
they're actually
largely undamaged.
[Narrator] The concrete bridge
the train hits has collapsed.
[Shini Somara] Carriage 4
clears the bridge but
slams into some nearby trees.
Carriage 5, half makes
it under the bridge,
the other half is crushed.
And carriage 6,
a restaurant car,
is completely compressed
to just six inches.
[Narrator] This suggests that
the accident begins between
carriage 2 and carriage 4
and the evidence
backs this up.
[Andrew Steele] It's the
third carriage that's
really suffered here.
The back of that has derailed,
and it's swung off to the right.
[Narrator] This points to
the disaster beginning
with the derailment
of carriage 3.
What causes that?
A piece of vital
evidence comes from
the minutes before the crash.
-We have various witness
statements, but there's one
that is particularly important.
This comes from Jorg Dittman,
who was sitting in
the front carriage.
According to
Mr. Dittman's statement,
a huge piece of metal shoots up
between his wife and son.
So, he runs off
to tell the guard.
-Dittman says that the
attendant refuses to pull
the emergency brake until
he has personally verified
the damage because that is
standard Deutsch Bahn policy.
But unfortunately, just as
they walk through that door,
the train crashes.
[Narrator] Analysis of the
piece of metal that Dittman
sees reveals there is only
one thing it can be,
the outer rim of a train wheel,
and photographic
evidence shows damage
to railway sleepers
several miles back
from the crash site.
Which must have been caused by
the bottom of the broken rim
protruding down through
the carriage floor
and hitting the track.
-And that ties in with
Dittman's witness statement
because he says that the
carriage was swaying around
quite violently,
probably because of this
piece of loose metal.
[Narrator] But if this rim
causes the disaster,
why doesn't the accident
happen immediately,
rather than miles
down the track?
Very close to the
collapsed bridge,
there is evidence of
an anomaly in the track.
A section of guard
rail is missing.
Guard rail is used along the
edges of the track to keep
the wheels on the
rails at junctions.
At Eschede it
has been torn out.
[Maggie Aderin-Pocock]
This guardrail must have been
ripped up by this
protruding piece of metal
from the rim of the wheel.
[Narrator] That fits with the
evidence found in carriage 1.
-They find the guardrail a few
feet away from the wheel rim
and it's penetrating
from floor to ceiling.
[Narrator] This is a much
larger piece of metal than
the thin wheel rim.
[Andrew Steele] Imagine this
huge rail smashing up through
the bottom of the carriage.
That would be enough to
lift that whole carriage up.
[Narrator] Video show that the
rear axle of carriage 1 is
off the tracks.
The obvious cause appears to be
the impact with the guardrail.
But carriage 1 is
almost undamaged
and it's clear from
the accident scene
that the disaster
begins with carriage 3.
So, what actually happens?
[Shini Somara] If you look at
the track layout, there's a
set of points and switches
which divert the train off
the main line to
the branch line.
[Narrator] By the time the
train reaches these points
all the evidence suggests that
the rear wheels of carriage 1
have already derailed.
[Andrew Steele] Those
switch rails can be knocked by
something hitting them.
So, for example, a pair of
wheels are no longer
fully on the track and if that
switching were to happen,
then the train would be
diverted from the main line
that it's currently speeding
along onto the branch line.
[Narrator] The evidence from
the crash damage suggests the
front of carriage 3 clears
the points before they finish
swapping to the branch line.
But the rear is diverted,
taking all the carriages
behind with it.
[Andrew Steele] So now we've
got a situation where the
front part of the train is
shooting down the main line
and then those rear carriages
have been directed onto a
branch line and all of this is
happening at 125 miles an hour
and that's enough force to
rip the train into two and
explains why the locomotive
was found basically intact,
quite a long way
down the main track.
[Narrator] It's now clear what
causes the initial derailment,
but most of the devastating
damage is caused by the
bridge collapse that follows.
Why does the bridge fail?
[Narrator] The high-speed
train at Eschede is traveling
at 125 miles per hour when
it derails just before
reaching the road bridge.
-If we're trying to work out
why the bridge collapsed
we need to look at
the pattern of damage
on those carriages.
And carriages 1 and 2
are looking largely intact,
but the right-hand side
of carriage 3 is really,
really badly damaged.
[Narrator] Carriage 3 must
have hit something side on and
that fits with the evidence
that the points are switched
while the train
passes over them.
[Shini Somara] The first
two carriages make it
under the bridge.
The second half of carriage 3,
the back wheels
go down the branch line,
twisting the whole carriage,
moving it sideways,
slamming it into the bridge.
[Narrator] The bridge is
supported by concrete pillars
at the trackside.
In this accident, they are
a fatal design weakness.
The damage to the derailing
carriage 3 tells us that
it must have hit these
vulnerable pillars at
very high speed.
Without their support, the
bridge collapses on the train
as it passes underneath.
-Any carriages coming along
behind have nowhere to go.
So, they just plow
into the carnage.
[Narrator] 88 people
are severely injured.
101 are killed.
It all begins with the
failure of a steel wheel rim.
-We know how the disaster
happens, but the big question is
how does the rim come off
the wheel in the first place?
[Narrator] The maintenance
history of these trains
reveals that the wheels have
been an issue in the past.
-If you look at the
early high-speed trains,
their wheels are made
out of a monoblock,
a solid piece of steel.
The problem with the
monoblocks is they cause
lots of vibration and this was
particularly noticeable in the
restaurant car where the
glasses would clink together.
-So to provide a more
comfortable ride
for the passengers,
these monoblock wheels
were replaced with
what is called a
duo block wheel.
This is a wheel
in three parts.
There's a central hub,
then a thin layer of rubber,
about 20 millimeters thick.
That's a bit less than an
inch, that absorbs some of
those shocks and then a
steel ring around the outside,
which is called the tire and
this construction makes a
much more smooth ride for those
who are inside the train.
[Narrator] Duo block wheels
are fitted on the Eschede train.
-We know that somehow
that steel tire around
one of these duo block wheels
comes completely off and
shoots through the floor
carriage number one,
the question is how and why?
[Narrator] The clues lie in
understanding the mechanics
of how the duo block wheel
behaves at high speed.
[Shini Somara] Because of
the flexible nature of the
rubber inner rim, you've got
this constant distortion
of two steel parts.
That's what contributes to
the vibration because at
high speeds you're moving
from a circular shape
to an oval shape.
[Narrator] This constant
flexing slowly weakens the rim
through a process
called metal fatigue.
-If you wanted to break
a paperclip, for example,
you would just keep bending it,
fatiguing it, making it weak
and that's exactly what happened
to the outer wheel rim.
[Narrator] But fatigue
cracks take time to form.
Why aren't the warning
signs spotted during
routine maintenance?
[Maggie Aderin-Pocock] One of
the most shocking things were
the witness statements by
the Deutsche Bahn Engineers.
Rather than conducting vigorous
safety checks on the wheels,
they were just doing
a visual inspection.
[Andrew Steele] The obvious
problem with a visual inspection
is that crack needs
to be big enough to see,
and you're just never going to
pick up these tiny hairline
fractures that are typically
found with metal fatigue.
[Narrator] There is one final
alarming piece of eyewitness
evidence about the
actual train that crashes.
-On the weeks leading
up to the crash,
staff traveling on ICE 884
mentioned increased
noise and vibration
coming from that
particular set of wheels.
[Narrator] This is almost
certainly a warning sign
that the wheel rim is failing.
-Unfortunately,
nothing was done about it.
-The sad thing is that this
whole disaster might have
been averted if the
train company had just been
more diligent with the way
it maintained its trains
and their wheels.
[Narrator] There is
now enough information to
reconstruct the
chain of events that leads
to this tragedy.
It begins seven years earlier,
with the introduction
of a new type of wheel.
-A few minutes
before 11:00 a.m.,
the ICE 884 is traveling
towards Hamburg at
125 miles per hour.
The outer rim of the wheel
snaps off and punches up
through carriage 1.
[Narrator] The broken wheel
rim rips up a guard rail.
This lifts the rear axle of
carriage 1 off the track,
derailing it.
[Andrew Steele] Seconds later,
as that derailed wheel hits a
switch rail, it switches the
points and redirects the back
part of the train
onto that branch line.
[Shini Somara] The locomotive
and the first two carriages
make it under the bridge,
but the third carriage
twists sideways,
slamming into the bridge
and the bridge collapses.
[Andrew Steele] The rear part
of the train smashes into the
collapsed bridge in the
massive carriages that have
been crushed beneath them.
This whole thing has just
taken a few seconds,
and yet 101 people are dead.
[Narrator]
Following the disaster,
there are major changes.
The bridge is rebuilt with
a cantilevered design that
doesn't have the
vulnerable pillars.
Duo block wheels are
immediately removed from
every ICE train
and replaced with
the original monoblock design.
Today, ICE trains
remain in service,
carrying millions of
passengers every year.
Captioned by
Cotter Media Group.