Episode 1 The Fifteen Billion Pound Railway

This is a drone's-eye view

of an extraordinary endeavour

almost entirely hidden from sight.

While shoppers and city workers

pound London's pavements above ground,

this secret army of more than 10,000 workers is pulverising the rock and

clay right beneath their feet.

They're building Crossrail...

..a brand-new underground railway costing almost £15 billion.

All right, John!

It's one of the most ambitious rail projects in Britain

since the time of Brunel.

Ready!

I don't think we've seen anything to the scale and complexity

of Crossrail before. Certainly not in my lifetime.

In the last series, we followed engineers burrowing the maze of

subterranean tunnels for the trains to pass through.

Pinch up, nice and easy.

You know what? This is real, it's coming,

we've been working night and day.

And now, for the second part of Crossrail.

Give us a shout if that's going to touch that handrail.

Now, we follow workers as they embark on the crucial final phase.

Full stop, there.

Engineers face the huge challenge of constructing the tracks...

..trains...

..platforms...

Two notches up again!

..and stations.

Turn it a little bit so you face to me.

It's a constant battle to avoid snarling up the streets...

This is one of the busiest roads in London.

You've got thousands of pedestrians walking past us.

Pressure's on.

..or causing them to cave in.

The wall hasn't collapsed then yet, no?

Great, big, megaproject all across London.

Every station is feeling the pressure and is feeling the heat.

For the last three years, cameras have been following crews as they

struggle to finish construction

so that the first train can depart on time.

It's tight.

-They're coming that way, yeah?

-They've got to be here before six.

Before we open, there's lot to finish.

All our reputations are at stake.

We've got to get the track in, we got to get platforms, and then we've

got to get out of the way, cos the trains are coming through.

This is the exclusive inside story of the race to complete

London's new underground railway.

5am, Farringdon,

the heart of London and a historic hub for trade in the capital.

As merchants at Smithfield Market set up their stalls...

Uh-oh.

All right, ready to go.

Down, down, down.

It's not the eight levels going down, it's the coming back up.

Crossrail project manager Linda Miller is descending 30 metres

down into the bowels of the earth.

All right, so we're not too far to go.

Linda is joining workers to witness a critical milestone

on the Crossrail project.

The 18th and final tunnelling breakthrough.

This marks a key moment.

For the last three years, eight giant drilling machines like this

have been excavating the earth to create the tunnels that Crossrail's

trains will run through.

So, there you are. You can see Whitechapel.

This final slab of concrete is all that stands in the way

of the tunnels connecting up so they run unimpeded

from the east to the west.

Yeah, OK.

It also marks the start of a new phase in this trailblazing project.

Over the last three years,

it has not been an easy dance by any stretch of the imagination.

This is an incredibly, incredibly important moment in time.

But this is also, for us, the starting gun of turning these

great, big, cavernous concrete spaces into functioning,

beautiful transportation systems for the next 120 years.

All eyes and ears are on it coming through at the moment

and it's a moment of tension, it's a moment of anticipation.

CLAPS, WHISTLES AND CHEERS

Oh!

With one final push...

APPLAUSE

..tunnelling on Crossrail is complete.

Congratulations.

Congratulations, that's fantastic.

Welcome to Farringdon!

Fantastic night.

Tonight's a night to be celebrated.

It's a hard-fought success.

As workers carefully dismantle this last tunnelling machine,

a critical new chapter in this ambitious scheme kicks off.

Crossrail is a story of huge, huge moments and giant accomplishments.

I've got 100 great big things I've got to worry about every day.

And going forward in the future, I have a million little things

to worry about every day.

Now, it's a race to the finish line.

Crossrail is a brand-new, east-west railway

being built directly below the heart of London.

This new line is designed to ease the strain on the existing

150-year-old London Underground network that, today, struggles

to cope with peak demand.

Crossrail is a huge new railway for London.

So, it's going to be able to carry 200 million passengers a year,

a 10% increase in capacity, at a stroke.

Crossrail will help to keep London moving

for the next many, many years.

The new line will run overground from Reading and Heathrow

in the west...

..straight underneath central London.

It will plug directly into key mainline train stations,

connecting the bustling West End to the historic Square Mile

and the thriving East End,

before terminating at Abbey Wood and Shenfield in Essex.

120km of new railway will link to the rest of the Tube.

Heathrow Airport will be just 26 minutes

from London's main shopping district, Oxford Street,

a journey that currently takes almost an hour on the Tube.

It's one of the biggest engineering projects in Europe.

A big construction project is a little bit like an orchestra.

You've got many players, lots of skills, different skills,

and they've all got to be playing to the same tune.

The complexity that goes along with scale is, of course, intense.

Railways are very difficult things to design and build.

Construction work on Crossrail began in 2009.

The first major challenge facing engineers was to dig out

42km of train tunnels underneath central London.

Now, with tunnelling complete...

..they face the Herculean feat of fitting out the platforms...

..laying the tracks...

..building a fleet of new trains...

..and constructing ten cavernous new stations in central London.

And hold it there, stop.

With the first trains scheduled to run in less than three years...

..the clock is ticking.

The biggest station that needs building along the line

will be at Farringdon.

Farringdon is home to Smithfield Market,

the largest meat market in the country.

And the city's world-famous diamond crafting quarter, Hatton Garden.

Once complete, Farringdon will become one of Britain's

busiest train stations, servicing 150,000 passengers a day.

Thank you.

Oh, there you are.

Every day I bounce out of bed ready to come here,

and to come to work and feeling great about it.

Linda Miller faces the mammoth task

of making sure its gates open on time.

This station is really going to be where the action starts

when the railway opens.

If you were to take the Shard,

which is the tallest skyscraper in Europe right now,

and lay it on its side, it would fit inside of my Farringdon station.

We're enormous in scale.

Our platforms are over 300 metres long.

What that means in the future,

if you're stepping off the trains at Farringdon you need to know which

way you're going because if you walk in the wrong direction you're going

to be half a kilometre from where you wished you were.

Linda is no stranger to challenges like this.

A former US Army pilot and paratrooper,

Linda trained in engineering and helped build

Nasa's launch complex at Cape Canaveral in Florida.

She has spent the last four years rebuilding these Victorian train

tunnels that will form part of the Crossrail line.

But constructing Farringdon's £375-million station

will be her biggest test to date.

Farringdon is the most expensive of the stations

on the project.

Looks great.

Afternoon, guys.

We get every day that we're spending the taxpayers' money

and we care about that because we're part of those people

paying for this.

Linda's team's first task is to dig out

two huge eight-storey-deep holes.

These will form the ticket halls for Farringdon Station.

Underground they must widen the freshly dug tunnels

to create its platforms.

Then dig out passageways and escalator shafts

to link them to the ticket halls and entrances.

Excavating the earth to build the platforms could be treacherous.

Geological fault lines run right across the site

and an ancient river once flowed through here,

leaving the earth pitted with unstable pockets of sand and water.

If the team hit these areas as they dig, the earth could cave in around

them, so they must be on guard.

While workers above ground dig out the huge holes

in which they will build the station's ticket halls...

..30 metres beneath the site, the sandy earth is making

excavating the train platforms tough going.

So, this is what we've got.

Here's a bird's-eye view looking down on the station.

We're facing the most dangerous type of soil.

There's not one but three different fault lines right through the middle

of our work.

Fault lines present a danger to the long-term durability of

the railroad itself.

The soil changes, slips quite literally three to five metres.

It provides a pathway where you could have cracks,

where you could have future flooding.

They need to double the width of the train tunnels here

to create the platforms.

They use excavators to carefully claw into the unstable earth.

'The team are digging out a mountain out from under London.'

Simultaneously with the dragging away of that soil is the spraying of

concrete on that face so that the face doesn't fall in on you.

All right, Jez!

As it flies towards the wall under pressure

it's dry, just barely smack at the time it hits the wall.

The mining is going well, but we're never complacent.

We never say, "Oh, yeah, we're all that good,"

because that's the day it goes wrong.

Once dry, they line the platform walls with a plastic membrane.

The membrane is fully waterproof, tough,

durable and is going to form a seal around our entire tunnel.

We are going to be wrapped like a Christmas present.

It takes five-and-a-half football pitches' worth of the membrane to

protect the platform and escalator passages

that lead up to the ticket halls.

See, doesn't that look so astonishing?

For a while it's going to be orange world around here.

Two stops east lies the vibrant community of Whitechapel.

Home to the foundry that cast the Big Ben bell

and famous for its bustling market,

which has been the heart of the community for more than 300 years.

One of Crossrail's ten central London stations

will sit in this district.

The station here won't be completely new.

Instead, engineers are undertaking a £111-million overhaul of

Whitechapel's existing Tube station, built in 1876.

Their aim is to create a modern,

open-plan station to plug Crossrail trains

directly into the existing Tube and overground services

that stop here.

While workers complete Whitechapel's train platforms below ground...

It's all right, I'm out, mate.

..proud Yorkshireman Jim Forrest leads the team

gearing up to build the new station above.

It will be one of Jim's toughest jobs in

a career of trailblazing projects.

I've worked in construction since 1960.

I worked on the Humber Bridge,

I worked on 1,000-foot concrete chimneys,

nuclear power stations, coal power stations.

You name it. This is the highlight, what I'm doing now.

I did retire in 2003 for a fortnight and then came back.

When I realised it wasn't a holiday I was on,

I thought I'd better look for something to do.

Depends what comes up.

But it would be a good project for a swansong, really.

Whitechapel is one of the most confined and most complex

construction sites along the entire Crossrail line.

Market stalls, roads, and residential buildings

hem the site in.

Whitechapel Station is one of the most logistically complex projects

I've ever worked on.

We've got very little space to work, above and around a live station.

We've got schools and public and sports centres.

I think the station layout is not very good for modern day.

The passenger flow is very poor.

There's no step-free access

and it looks as though it's just been thrown together.

What we've got now is not fit for purpose

so we've got to change it.

The layout of the existing Whitechapel Station

is so haphazard that it's the only place

where London Underground Tube trains pass right over

the mainline overground trains.

Squeezing a conventional station

into such a chaotic space is impossible.

So engineers must build the new ticket hall

inside a unique 180-metre-long

floating bridge that passes right over the site.

This station bridge will run north to south connecting down to

the Crossrail tunnels channelling passengers to existing train lines.

A skeleton of 6,500 pieces of steel will form its frame.

This will allow the station bridge

to hang from the surrounding Victorian infrastructure,

giving the impression that it floats above Whitechapel.

352 panes of glass will allow light to stream through the structure.

Special aluminium roof cladding will absorb train noise,

while carbon-cleaning sedum plants will top out the elevated concourse

giving this 19th-century station a 21st-century makeover.

If I was given a choice I would maybe say, yes,

we should flatten this and build a...

But then it wouldn't fit in, it would be like a carbuncle in amongst the rest of it.

So you've got to be respectful of what other people want.

Keeping the existing station operational

while they build the new one

above it makes this project even more difficult

for Jim and unpopular with commuters.

Whitechapel is open but this particular entrance is going to be

out of service until about 2018

while it's being refurbished, Crossrail is being introduced.

It's... There is now...

There's a new pedestrian crossing right opposite the exit

to the station, though, so you just carry on.

It's the same distance.

I've been hit by the station closure this morning.

Had to go from one station to another

and didn't really know my way there.

There's always work going on and it's not just here

but it's all over London.

I'm going to have this cup of Yorkshire Tea

and then I'm ready for the day.

Two lorries. Are they coming that way, yeah?

Yeah, they are coming that way.

5am.

Jim's waiting for the steel pieces of the station bridge,

that have been prefabricated in the Netherlands, to arrive.

Once they've squeezed onto site

Jim's team must assemble them into much

larger sections and then use cranes to lower them

into position over the train lines.

They've got to be here before six, so there are two en route,

one imminent, and the other one not far behind it.

We've got to get them off the road by six

because that's when the traffic order is timed out.

20 minutes now. OK.

-HORN BEEPS

-Here we are.

The loads are here now.

There's traffic marshals going down to block the traffic down that end.

We've also got traffic marshals down that end to stop the traffic there.

These lads are controlling the rear axle steering so it helps them get

round a very tight radius.

You can see how much there is,

at least a metre hanging over either side.

We don't have a lot of clearance on the street furniture.

The loads look big.

The shape of them makes life difficult for them.

Here we are.

The road is now open. And it's open with seven minutes to spare.

Now we need to take this down to the crane to allow the other three

lorries to drop back to make sure the front lorry isn't blocking

the pedestrian way when the market opens.

With 6,500 pieces of steel to guide in and assemble over the next few

months, Jim's team has their work cut out.

Another one bites the dust, eh?

Yeah!

The markets here are at the heart of community life.

But some traders have been forced to move their pitch while

Whitechapel Station is rebuilt.

My shop was in front of that station, OK?

So customers basically used to come in the street.

But now it's a little bit further.

But basically it's only for two years,

so after two years more customers

will come because of the Crossrail and other stuff.

So it should be better.

Two stops west...

..Linda's 500-strong team has run into problems

building the new station at Farringdon.

The track teams, they're like a juggernaut,

so we've got to get out of the way.

This is one of the busiest sites in the entire project,

and, in fact, the busiest I've ever been on in my career.

But there's a new problem to solve and this is a really tough one.

The team has dug out the eight-storey-deep holes

that will form the ticket halls for the station

and are now building its walls and floors.

We've had three pieces arrive on site on Friday

that we couldn't get in over the weekend.

That is going to be the hardest of them all.

Underground there's a battle for space.

As the walls of the platforms close in, it's become almost impossible to

shuttle crucial materials and equipment

down to this crammed subterranean site.

This jam could hold up the track-laying team

that is fast approaching this stop.

Right on the tail of our tunnelling operations,

the track laying has begun

out in East London and is heading towards us.

So, the track layers need safe,

clear access from street level down into the tunnels

that is not through the stations.

We lower the unit down through these first two vents and

then we would just remove the jacks.

One thing about being an engineer,

especially in the construction industry,

is you're always having to think on your feet.

To get equipment down underground faster

Linda's team hatches a plan to dig out an emergency 30-metre-deep

vertical shaft.

This will plug into the tunnels below to give workers direct access.

Building this shaft won't be easy.

Above ground, the site is crowded.

The only available space to dig down is on the neighbouring Tube line

platform at Barbican Station.

The shaft will sit less than two metres away from live Tube tracks.

The team digging it must remain focused

or they could miss their target.

Or delay the Tube trains that need to pass through this station.

Sometimes you need a plan B.

Sometimes a plan C,

a plan D and E, until you get it right and get what you need.

The pressure is on Steve Parker to construct the shaft fast.

-We'll sign in and have a look here.

-Yeah, no problem.

-We're all right going in, though?

-Yeah, yeah, you're all right.

'We're currently working 24/7 at Farringdon.'

The pressure's always on to get the job completed

and it's a big motivator.

It's a big motivator.

Ideally, you'd be building this sort of shaft in the middle of

a green field impacting no-one.

It's a five-metre diameter shaft.

It's sunk by basically,

there's a steel cutting edge on the bottom ring

and once we've got enough

rock excavated we basically can shove the ring down.

Steve's team must excavate more than 1,000 tonnes of clay

to create the shaft.

As they dig down they must line its walls with concrete panels.

The panels lock together to form a ring that stops the earth caving in.

Hydraulic jacks thrust the rings

down into the ground as they dig deeper.

They must work day and night to complete the 30-metre-deep shaft,

with trains passing right alongside.

It doesn't always run super-smooth.

You're working with quite large sections of concrete,

they're quite big, and you're lifting them into position

with a crane.

There is a bit of sort of jiggling about that you need to do

to get the ring built.

They've got to try and keep the shape of the ring,

so when they shove it

it goes down plumb and level,

so it's very important that you need to keep the diameter right,

so they're constantly measuring.

After each plate is positioned, they measure it to make sure it's at

the right dimension.

Yo. Whoa, whoa, whoa.

Final segment's going in.

It's what's known as keying up the ring.

This is probably the trickiest part of the ring-building process.

So, the thing is built. 15 left to do.

Steve's team must keep up the pace

so the track layers can pass through Farringdon on time.

In the city's business district...

..engineers are hard at work building another brand-new station

for Crossrail trains at Liverpool Street.

Digging out the massive 23,500-square-metre hole

for this particular ticket hall

creates a unique portal into the past for Crossrail's

lead archaeologist, Jay Carver.

You don't really get the opportunity to dig large holes deep into the

ground and get that full sequence of London's history

that spans back 2,000 years.

Crossrail's been really interesting for archaeologists because of its

scale. The route east to west across London has provided this kind of

unique slice across the city.

Over the past five years, Jay's team has unearthed over 10,000

extraordinary finds at more than 40 different sites.

From prehistoric bison bones found in West London,

to 25 skeleton victims of the Black Death found in the east.

Every site has a significance,

hence why we are carefully revealing the remains and recording it

before it's gone.

Crossrail station at Liverpool Street

will be the deepest along the line.

We've got as many names for mud as Eskimos have names for snow.

And the deeper they dig, the further back in time Jay's team can

investigate the city's history.

We're actually standing in the excavation for the new ticket hall

at Liverpool Street for Crossrail.

And we're looking for a feature, and that's a Roman road.

So, Rob, let's take a look at this map that we've got.

A road has been postulated outside the city walls

for a number of years.

A part of it was found in Eldon Street,

which is one block over that way, during the '90s.

The Roman city of London, Londoninium,

was founded nearly 2,000 years ago.

Its two-mile long defensive wall

protected a complex network of roads.

Many of these formed the basis of London's modern streets.

At its peak, Londinium was home to 60,000 citizens,

making this small settlement tough to travel across without delays.

Jay and his team are hunting for evidence

of a Roman North Circular Road that, like Crossrail,

ran east to west around the walled city,

cutting travel time through early London.

We know a lot about the central and western areas of the city, don't we?

But this is a really great opportunity

to really try and understand this part of the Roman city

and what's going on outside the city wall.

60 archaeologists are working around the clock to excavate this huge pit.

But no-one knows for sure if they will find the lost Roman highway.

One stop west at Farringdon...

..it's taken Linda and Steve's team

eight weeks to excavate the emergency shaft

beneath Barbican Station, giving access to the tunnels below.

Now the shaft is built, the materials are moving.

They're able to move as fast as they can, 24 hours round-the-clock,

doing what they need to do to pick up the speed

to deliver their part of the job.

With 15 months to go until Crossrail trains start to run,

workers race to shuttle the vital materials they need

underground to complete the platforms and lay the rails.

Gregg Purcell is responsible for installing

this section of the railway under Farringdon.

It's not often you get to work on a project of this magnitude.

It is something that is maybe a once-in-a-generation thing.

It's amongst the most logistically complicated programmes of work

I've ever been on in my career.

If one part of the production line fails

the whole production line fails.

Gregg's team need ingenious machinery

to help them lay 50km of track in time

for the trains to roll.

Track installation in the modern era

is a completely different animal than it was maybe 100 years ago.

In 1863, track-laying gangs of up to 25 men

completed work on London's very first underground Tube,

the Metropolitan Line.

Working in shifts they could lay up to 150 metres of sleepers and rail

in a day.

Today, these machines can lay over four times that.

On Crossrail, we've got a fleet of hi-tech vehicles.

We've got a 465-metre-long concreting train.

We have a multipurpose vehicle to work in tunnels.

This machine is called the multipurpose gantry.

There's four of these on Crossrail.

And they're worth about £1 million each.

It looks like a Transformer and it can change its shape

depending on what conditions it's working in,

whether it's lifting rails,

lifting bits of reinforcement.

The whole machine can take 15 tonnes in load.

This mechanical monster can lay up to 600 metres of sleepers a day.

Multipurpose gantries are a godsend

and I would struggle to understand how

we'd build a project like this without that sort of kit.

Once the trains start running, these tunnels will become noisy.

But right here Gregg faces a challenge like no other.

He needs this section of the tracks to make almost no sound at all.

Here, we are directly beneath the Barbican.

Right directly beneath.

Opened in 1982, the Barbican Centre is a hub for arts and culture.

The centre's most prestigious performance space, Concert Hall One,

sits two storeys below ground.

The Barbican Centre's the home of the London Symphony Orchestra,

presents regular seasons from the Royal Shakespeare Company.

It really is one of the truly great artistic centres in the UK.

A lot of music is about exploring the relationship

between the very quietest sounds and silence.

And, therefore, a lot of performances really focus

on that magical area of audibility.

And there's the rub.

The Barbican's Concert Hall One sits

just 17 metres above Crossrail's tunnels.

Noise or vibrations from trains

could travel through the earth and

into the concert hall, disturbing performances.

To guard against this,

Crossrail engineers have developed ingenious floating tracks.

Unique concrete slabs of rail and sleepers

that sit on special springs.

When a train passes over the springs they should absorb all of the energy

and noise before it reaches the concert hall.

Floating track slab allows that noise to be brought down even lower.

On the surface you won't hear anything

when you're watching Hamlet.

It takes over 150 tonnes of concrete reinforced with steel bars to form

each 30-metre-long floating track slab.

So what you can see behind you now

is all the guys assembling the track.

We've got all the reinforcements complete.

The spring housings are all installed.

We've got all the rail.

And this slab is being set up to cast the concrete on top.

Ready to go.

The concrete that we pour here is called MagnaDense.

A very expensive mix of concrete.

We pay around £1,000 a cubic metre for it.

Traditional concrete costs may be a tenth of that.

The reason it's so expensive

is because it's upwards of 40% heavier than normal concrete.

That in turn will then result in very,

very low to the point of hardly any vibration in the Barbican Theatre.

We treat it a little bit like gold on the project,

so we had to keep the waste concrete to an absolute bare minimum.

Are we there, Stu?

There we go.

That's the liquid gold coming out there.

They flush foam balls down the pipe

to eke out every last drop of MagnaDense.

Very impressive.

Once set, they screw the springs into place

on the underside of the slab

and raise it to its final height.

So this is a section of the floating track slab that we've cast.

We're going to be putting the springs in there

and we will then jack up the slab.

OK!

When you're in the Barbican Theatre, watching whatever show

you're watching, you won't hear a thing.

With the slabs cushioned by the springs

they can set the rails on top.

But they'll only know for sure if their silent track system works

when the trains start to roll.

With this crucial section of the railway in place

the team can pick up the pace through the rest of the tunnels.

Two stops east in Whitechapel...

..Jim's team is fitting together the huge pieces of steel that will form

the area's new floating bridge station.

Can we make sure them flanges don't bite into the tarmac?

Space here is so tight that they have no option

but to assemble the bridge

sections in a neighbouring school.

Yeah, that's enough on that one.

Luckily, school's out today. It's Sunday.

These elements are all fastened together by hand.

This is probably similar to putting together a flat-pack wardrobe and

you just hope that at the end of the day

you haven't got two or three nuts and bolts left.

Just move around to your left for me as you're going.

We're putting the big pieces of steel together.

Once they are together they will both be lifted simultaneously over

onto the rail line.

We connect big blocks to big blocks to make a mega block.

Once assembled, Jim's team must use cranes to swing each section into

position over Whitechapel's mainline train tracks.

The line is closed for today's operation,

but must reopen in less than 48 hours

ready for Monday morning's rush hour.

He needs everything to run like clockwork to avoid chaos.

Come down on that one. Come down on that one.

The first big section of bridge is ready to lift.

But there's a problem.

Bad weather threatens to shut down the entire operation

and could delay the project.

Down to your left for me as you're going.

We're taking our time.

This is a difficult operation to carry out

because the alignment has got to be precise.

One of our main concerns is monitoring the wind.

It does make the loads unstable.

We obviously have to keep an eye on it all the time.

Tall buildings hem this site in.

They channel the wind into a strong tunnel of air.

If the wind gets up during the big lift,

there's a risk it could blow the bridge sections off course

into the residential buildings next door.

I can hear the tension coming into the slings and shackles now.

CREAKING

The load is now being lifted.

See the steady movement of the crane lifting it up.

It takes great skill to carefully manoeuvre

this 40-tonne chunk of steel

away from the buildings and down towards the railway tracks.

-OVER COMMS:

-'Another little flick to your left for me.'

'That's nice like that.'

So far, so good.

The section must slot into this 25-metre-long gap

that stretches between this handrail and this crossbeam.

It's going to be tight.

'Go to your left a bit more, mate.'

'Keep it coming down.'

ALARM SOUNDS

'All stop there for me a minute. All stop there.'

Just as they near the drop zone, they hit another glitch.

What do you need to do? Take a foot out of it?

OK.

Such a tight fit with the handrails that to get the unit in they've

got to cut a small gap in the handrail.

They must act fast.

A hold-up here could stop trains

running tomorrow and result in Crossrail bosses

being fined over £100,000.

If they cut the top one off they may well have to cut the second one off.

Are you ready with your Podger, mate, yeah?

-Have you put your Podger in?

-Yeah.

Right, how is that looking on that handrail now?

-That looks pretty sweet.

-Right, we happy to come down, yeah?

I'm ready. You ready, Adam, you all right?

-Are you ready?

-'Yes, start bringing it down slowly, then.'

OK, Dave, nice and steady, mate.

A few inches to go, lower off.

Give us a shout if that's going to touch that handrail.

Just keep lowering, Dave.

You might need to get a bolt in, mate,

because that one's now slightly out of line now.

All right, Dave, inch to go.

Right, that's us in.

You're looking at a very happy chappie.

Yeah, it's gone really well, that.

But with more than 6,000 pieces of bridge yet to assemble

there's still a huge amount of work for Jim's team to do.

One stop west at Liverpool Street...

..Jay Carver's team of archaeologists have hit pay dirt.

It's quite extraordinary, really.

We're several metres down from the Liverpool Street pavement.

Right below here we have the surface of a Roman road that would have seen

the feet, the hoofs, the wheels of Roman carts and traffic.

What we've found so far is there's actually

a really well-constructed road,

perhaps seven or eight metres wide in its early phases

and then expanded to about 11 metres wide.

Now, that's quite a major highway.

This Roman highway, wider than a dual carriageway,

would have helped people take a short cut across the busy city,

just like Crossrail's train line today.

The road is literally heading kind of diagonally across our site

like that. Generally east-west.

It's quite likely this road is part of a network

of external roads around the city of Londinium.

Possibly we're talking here about a ring road.

It's absolutely chock full of debris and rubble,

no doubt brought in from other places in the city.

We can see lots of Roman tile, lots of pottery, lots of animal bone,

the occasional human bone as well.

It's been incorporated into this cemented surface.

It takes us back to a time 2,000 years ago when transport was just

as important to people living in London

and a road like this probably did

reduce congestion in the city itself.

The digging will soon be over here, but Jay's work won't be done.

His team will analyse all of the discoveries made at Crossrail sites

in more detail to slowly piece together

the secrets of London's lost past.

In Farringdon...

..Linda's team has finished work

on the station's new underground platforms...

..and the tracks are down.

Looks great. Afternoon, guys.

Above ground, the walls and floors of the ticket halls are in place.

Now Linda faces a race to complete Farringdon Station's grand entrance.

It must plug directly into the Thameslink station next door.

In the future you will come into the doors,

you'll be able to continue to walk straight to get on the Network Rail

trains, or you'll be able to turn

and go down into the Crossrail station.

Commuters will pass beneath a cavernous diamond-patterned ceiling

to enter the station.

To build it, Linda's team must piece together

105 bespoke concrete segments.

This will be like assembling a giant jigsaw.

42 concrete-coated steel beams will form the diamond-shaped frames.

63 concrete panels will sit inside.

Craning these awkward-shaped pieces into position without crashing into

the busy Thameslink station next door will test the team's mettle.

Plugging in to a live railway station

has its whole set of new challenges.

This is the last big part of the build and it's going to be tough.

Andy Scholes is working with Linda on this stage of the build.

This is our main feature of Farringdon Station.

90% of what we've constructed here on site is buried.

It's not just a ceiling.

This is a statement piece.

This is what everyone will see

over the next 120 years when they enter Farringdon Station.

The pressure's on in order to get this right first time.

First task, erect a network of steel supports

to prop up the heavy ceiling as they lock it together.

It's looking really good at the minute.

With the supports in place, Andy's team can start work on the ceiling.

It's a diamond shape and it's in keeping with the local area

and it gives a huge visual, striking welcome mat.

The ceiling's diamond design is inspired by the area's history.

The nearby Hatton Garden jewellery quarter

has produced and sold diamonds for over 150 years.

-ARCHIVE:

-Here's a street which if it isn't actually paved with gold is

still the richest highway in the world.

Since the 1930s, this area of London has been responsible for 90% of

the world's diamond distribution.

Diamonds, the world's most precious commodity.

But then, there's nothing too good for a woman, now, is there?

Sections of Farringdon Station's diamond-inspired ceiling

are being made by hand at this factory in Derbyshire.

Each concrete segment is cast in a bespoke mould and takes two weeks to

create and cure.

Once set and polished, workers need to drive each of the 105 pieces

130 miles into central London,

where they must fight for space to get onto Andy's cramped site.

This is one of the busiest roads in London.

You've got thousands of pedestrians walking past the site watching and

seeing what we're doing.

It's quite important that we don't block up the traffic so we need to

keep a through flow of traffic coming past the site.

We've now got a delivery coming in.

What they're going to do is they're going to hold the traffic and we'll

hold the public back to keep them safe.

HORN HONKS

The wagon's now on site and this will allow us

to check each individual piece to make sure

that they haven't been damaged in transit.

We don't want any chips or bashes or any chunks taken out of the beams.

Marvellous.

In the East End...

..Jim's team is making headway

building Crossrail's floating bridge station

across the mainline railway at Whitechapel.

This is what we've been building up to for the last year, 18 months.

And this is the culmination of a lot of effort.

They've had to shut down the tracks

for 40 days over a two-year period to assemble the base of the bridge.

But once down, Jim's crew pick up the pace,

erecting its walls,

curved canopy roof...

..and walkways, with fewer disruptions to passengers.

You've got to very gingerly stack them all in the right order.

If you put them in the right order

and secure them firmly you'll get the pyramid made.

All right? You all right?

With 6,500 steel components assembled,

the skeleton of the bridge is complete.

This is looking quite spectacular now that it's all coming to shape.

Yeah, it's looking really good.

Coming out the ticket hall you think,

"Wow, didn't there's so much space in Whitechapel!"

It must be the most spacious place going, is this now.

This is the concourse area.

This area through here is where the passengers will come up from

the London Underground lines.

It just shows you what is achievable.

It took a bit of Yorkshire grit to get to where we are now, yes.

Over the next few months, Jim's team will fit out the ticket hall

and top out the canopy with its glass panes and sedum plants,

completing Whitechapel's upgrade ready for Crossrail trains

to stop here.

Two stops west in Farringdon...

..Andy's team is gearing up to assemble the diamond-shaped sections

of Farringdon Station's vast ceiling.

To get all the pieces of this puzzle in the right place,

Andy needs to stick to his Bible.

What we have here is the plan of the ceiling itself.

Each piece is individually named and numbered so when they arrive on site

we know where we're going to lift them to.

If we lose the drawing then we're stuffed, basically.

It would be a really difficult jigsaw to do.

Pinch up, nice and easy.

The beams that make up the diamond-shaped frames

weigh up to ten tonnes.

'All clear.'

Lowering them into position,

right next to the operational Thameslink station,

takes a delicate touch.

Keep coming down.

This is one of the trickier lifts that we've got to do.

That's the ticket hall level.

If you listen out you can probably hear the announcements

from the train station.

INDISTINCT TANNOY ANNOUNCEMENTS

Yeah, very close.

We're moving it now millimetre by millimetre to get it into position.

Because we haven't got a lot to play with

next to the Thameslink station.

Yeah, down on that.

Touch down.

So they've got the beam touched down

but they just need to move it into the exact location.

It's a couple of mil off at the bottom

so they're working out how best to move it without damaging it.

So, as you can see, next to the Thameslink station

we're about probably 200 mil off.

They slowly slide the beam into position.

With the ceiling's frame in place

they can slot in the diamond-shaped panels.

Pinch up, nice and easy.

This is like a big jigsaw puzzle.

Luckily, you won't lose any of these pieces under your sofa.

That's it, mate, all clear.

Afternoon, friends.

Afternoon.

After eight years' work,

Farringdon Station is almost complete

and Linda gets her first glimpse of its grand entrance.

Wow, wow, wow, wow, wow!

That looks fantastic.

It's like when you walk into a cathedral.

It is a relief to finish the last of the big builds on site.

I suppose it's a little sad, too,

as it is whenever you accomplish something that feels great.

Say diamonds are forever,

but these diamonds are meant for 120 years at least.

With Farringdon's monumental entrance complete...

..the track team belowground head west towards Oxford Street

and Paddington.

As they put the finishing touches to the platforms and tunnels,

workers at Crossrail's Bond Street Station

prepare to welcome a very special visitor.

I'm down in the eastbound tunnel now at the far end.

Just checked the other boxes. Everything seems to be OK.

Today they're announcing the new name for the railway line

and are hoping for a royal seal of approval.

The Queen visiting the project

certainly starts to make the whole project seem that much more real.

It's just an honour, a once-in-a-lifetime opportunity.

I did my curtsy, yeah.

It's quite surreal to see her actually down in the tunnels,

but I feel it's a momentous occasion.

I couldn't be happier we're going to be the Elizabeth Line.

We're seeing that end in sight and it's created a whole new wave

of excitement from the team.

With Elizabeth Line trains due to start running from this station

in less than 18 months' time,

the pressure is now on to complete the rest of the railway.

Next time...

..we follow the race to the finishing line...

There's no second chances.

It gets the nerves going and adrenaline pumping.

Weight's coming on now.

..as workers battle to remodel Brunel's masterpiece,

Paddington Station.

Time is money here.

We have to stay on schedule.

And build the rolling stock.

It's a hell of a challenge.

Will they make it so that the first trains depart on time?

Oh, not fun.

I just want it to end now.

To find out more about urban infrastructures

and how cities are made,

order this free poster produced by the Open University.

Follow the links to the Open University.