0:00:02 > 0:00:04Underneath the streets of London...
0:00:04 > 0:00:06LOUD TAPPING
0:00:06 > 0:00:08..an army of more than 10,000 workers
0:00:08 > 0:00:11is building a brand-new railway.
0:00:11 > 0:00:12MAN: OK!
0:00:13 > 0:00:15Crossrail.
0:00:15 > 0:00:18Costing almost £15 billion,
0:00:18 > 0:00:21it's the biggest construction project in Europe.
0:00:23 > 0:00:25You need to get out of the way here,
0:00:25 > 0:00:27because trains are going to start coming through!
0:00:29 > 0:00:31One of the most complex challenges...
0:00:32 > 0:00:34..building the train tunnels
0:00:34 > 0:00:37that will pass underneath the River Thames.
0:00:37 > 0:00:42This water is surrounding the whole tunnel all the way up and through.
0:00:42 > 0:00:44It's tougher than anyone imagined.
0:00:44 > 0:00:45This water's just coming through,
0:00:45 > 0:00:49because our sealing isn't working the way it's designed to work.
0:00:51 > 0:00:54This job, it's going to be a bucket of spiders!
0:00:54 > 0:00:57This is the inside story
0:00:57 > 0:01:00of the engineers building London's new Underground.
0:01:02 > 0:01:04CHEERING
0:01:13 > 0:01:14The Thames.
0:01:15 > 0:01:17GULLS CALL
0:01:19 > 0:01:22The original superhighway that allowed London to grow.
0:01:22 > 0:01:24HORN BLASTS
0:01:36 > 0:01:39Today, a crucial new artery is taking shape
0:01:39 > 0:01:41that must pass right beneath this waterway.
0:01:46 > 0:01:48Crossrail -
0:01:48 > 0:01:50a 120-kilometre railway
0:01:50 > 0:01:53connecting Reading and Heathrow Airport in the west...
0:01:58 > 0:02:02..to London's major train stations...
0:02:02 > 0:02:04shopping districts...
0:02:04 > 0:02:09the square mile and the booming East End.
0:02:09 > 0:02:11It's due to open in 2018.
0:02:14 > 0:02:16The train tunnels for Crossrail
0:02:16 > 0:02:18need to pass under water at two key points.
0:02:22 > 0:02:25They must go under the Royal Docks at Custom House...
0:02:28 > 0:02:31..and under the River Thames near Woolwich.
0:02:39 > 0:02:41In their heyday,
0:02:41 > 0:02:44the Royal Docks were the largest enclosed docks in the world.
0:02:47 > 0:02:50Much of the old infrastructure remains in place today,
0:02:50 > 0:02:54including an old Victorian passageway, the Connaught Tunnel.
0:02:55 > 0:02:59The Connaught Tunnel runs underneath the water here.
0:03:00 > 0:03:02Linda Miller heads a team
0:03:02 > 0:03:05that is attempting to rebuild this old tunnel
0:03:05 > 0:03:09to make it suitable for modern high-speed trains.
0:03:09 > 0:03:12The mission for the Connaught Tunnel team is to turn
0:03:12 > 0:03:15a 135-year-old beautiful piece of Victorian architecture
0:03:15 > 0:03:18to a state-of-the-art, modern tunnel.
0:03:20 > 0:03:23The tunnel as it stands
0:03:23 > 0:03:26is too small for Crossrail's rolling stock to squeeze through.
0:03:26 > 0:03:28Well, I've been on some very exciting jobs.
0:03:28 > 0:03:31I've been lucky enough to build a new space launch complex
0:03:31 > 0:03:35at Cape Canaveral, Florida, and do tunnels in other beautiful cities,
0:03:35 > 0:03:37but I reckon this is my favourite job yet.
0:03:40 > 0:03:41I love the idea that
0:03:41 > 0:03:47we're bringing beautiful old... heritage railroad back to life.
0:03:49 > 0:03:52The Connaught Tunnel was built in 1878.
0:03:54 > 0:03:58Steam trains once ran through here, shuttling passengers and freight
0:03:58 > 0:04:00to the ferry terminals at North Woolwich.
0:04:03 > 0:04:05You may just see the old coke deposits
0:04:05 > 0:04:08and memories of the steam trains left above there,
0:04:08 > 0:04:11but actually what I see is a tunnel that's in cracking good condition.
0:04:11 > 0:04:15Fantastically well built, you know, really built to last.
0:04:22 > 0:04:26Dismantling and rebuilding this robust underwater tunnel
0:04:26 > 0:04:27will be a complex job.
0:04:31 > 0:04:32The Connaught Tunnel...
0:04:35 > 0:04:38..is a single tunnel for most of its length,
0:04:38 > 0:04:44except in the centre - under the docks - where it splits into two.
0:04:44 > 0:04:47Linda's team must completely rebuild this section
0:04:47 > 0:04:51creating a single taller, deeper and wider tunnel tube
0:04:51 > 0:04:54big enough for two Crossrail trains.
0:04:57 > 0:05:01The first job, then, was to start to deepen this tunnel
0:05:01 > 0:05:05and you can see that's just what we've done, cutting away
0:05:05 > 0:05:09and uncovering bricks that haven't seen the light in...in 130 years.
0:05:15 > 0:05:18This is Alex, and this is her patch.
0:05:18 > 0:05:22The work that needs going on here right in the heart of the job.
0:05:22 > 0:05:24This is my first project that I'm working on,
0:05:24 > 0:05:27so I'm really lucky to have such an interesting project as my first job.
0:05:27 > 0:05:30We're currently right below the docks
0:05:30 > 0:05:34and we're in one of the twin tunnels now. We need to turn it back into
0:05:34 > 0:05:37one tunnel, cos our new Crossrail trains aren't going to fit in.
0:05:37 > 0:05:39HOOTER BLOWS
0:05:42 > 0:05:43By the 1930s,
0:05:43 > 0:05:46the Royal Docks were some of the busiest docks in the world.
0:05:48 > 0:05:52Ocean-going ships delivered grain, meat and sugar to the UK
0:05:52 > 0:05:54from Australia and New Zealand.
0:05:56 > 0:06:00The vessels were so large that their keels often scraped the roof
0:06:00 > 0:06:03of the Connaught Tunnel that runs directly beneath the water.
0:06:05 > 0:06:08Engineers at the time were concerned
0:06:08 > 0:06:11that these boat strikes could cause disaster,
0:06:11 > 0:06:15so they removed part of the tunnel roof to lower the dock floor
0:06:15 > 0:06:19and sealed the tunnel from the waters above with steel rings.
0:06:20 > 0:06:24Linda's team needs to remove these rings.
0:06:24 > 0:06:27But a survey has revealed that there is a problem with the plan.
0:06:27 > 0:06:31It was always assumed that we could cut these cast steel rings out
0:06:31 > 0:06:34and replace them with rings that were slightly larger
0:06:34 > 0:06:38and that that would all be fine, because we had a really good, er,
0:06:38 > 0:06:42level of cover above the, above the crown of this old tunnel.
0:06:42 > 0:06:46So it was shock and dismay after we had our first divers
0:06:46 > 0:06:49clear away quite a lot of silt that was at the bottom of the docks
0:06:49 > 0:06:54and do a proper survey and find that actually we have no cover at all.
0:06:54 > 0:06:58The word we were worried about is, Oh, my gosh, as we try
0:06:58 > 0:07:00and cut these rings off of the crown of this roof
0:07:00 > 0:07:02and that much water is above us,
0:07:02 > 0:07:05catastrophic inundation or the sluicing in,
0:07:05 > 0:07:09the uncontrolled sluicing in of the Royal Docks into this tunnel
0:07:09 > 0:07:12became quite the real...er, well, terror, really.
0:07:15 > 0:07:18With little or no soil separating the tunnel from the water above...
0:07:20 > 0:07:24..removing the steel rings could cause a catastrophic breach.
0:07:27 > 0:07:31The only way to expand the tunnel safely is to seal off the passage
0:07:31 > 0:07:36with giant steel barriers called cofferdams, drain the water,
0:07:36 > 0:07:40and rebuild the tunnel, "top down", from inside this dry workspace.
0:07:42 > 0:07:44Oh, my gosh! Well, when we started,
0:07:44 > 0:07:46when this job was originally conceived five years ago,
0:07:46 > 0:07:48we were never going to be in the water.
0:07:48 > 0:07:51There was no cofferdam, there were no marine divers involved.
0:07:51 > 0:07:55It was all going to be just safely and tidily done from within.
0:07:55 > 0:07:59And, actually, the fundamental plan was broken.
0:07:59 > 0:08:01And then, to go and visit with our neighbours and say,
0:08:01 > 0:08:04"You know how for five years - eight years, really -
0:08:04 > 0:08:07"Crossrail's been telling you we're not going to close this passage?
0:08:07 > 0:08:09"We're going to close the passage."
0:08:11 > 0:08:14Shutting off the waterway here could cause chaos.
0:08:15 > 0:08:18It's the only way river traffic can pass to and from
0:08:18 > 0:08:21the city's largest exhibition space, ExCel,
0:08:21 > 0:08:23home to the annual London Boat Show.
0:08:25 > 0:08:27Linda's team needs to wait until
0:08:27 > 0:08:30the boats have left this year's show before closing the passage.
0:08:32 > 0:08:35They have a narrow time window before it must be open again
0:08:35 > 0:08:40for the next big maritime event - the Defence Show -
0:08:40 > 0:08:42when naval ships will need to get through.
0:08:46 > 0:08:49So we've only got six months to actually, um...build this.
0:08:52 > 0:08:54Rebuilding this old tunnel won't be easy.
0:08:59 > 0:09:01But south of the river at Woolwich...
0:09:04 > 0:09:08..Crossrail engineers are gearing up for an even bigger challenge.
0:09:09 > 0:09:13They're about to start building two brand-new sections of tunnel
0:09:13 > 0:09:17from scratch passing underneath the River Thames.
0:09:19 > 0:09:23In charge of the operation is Project Manager, Gus Scott.
0:09:25 > 0:09:28Boring under the Thames is a huge undertaking.
0:09:28 > 0:09:31Logistically, it's very challenging for us.
0:09:31 > 0:09:33We've got a lot of work ahead of us,
0:09:33 > 0:09:35but, er, looking forward to getting it finished.
0:09:35 > 0:09:40The new train tunnels will connect North and South London together,
0:09:40 > 0:09:45but digging them through the earth beneath the river won't be easy.
0:09:45 > 0:09:48The ground is made up of sands and chalk, which hold water.
0:09:50 > 0:09:52The tunnellers will face a constant battle
0:09:52 > 0:09:54to keep the water at bay as they dig.
0:09:58 > 0:10:02Excavating these tunnels carries the highest risk of flooding
0:10:02 > 0:10:03of the entire Crossrail project.
0:10:13 > 0:10:18So, to dig the tunnels, they need an extraordinary machine.
0:10:18 > 0:10:20Wow. LOUD CRUNCHING
0:10:20 > 0:10:21Take that!
0:10:21 > 0:10:23It's been built at this factory in Germany.
0:10:25 > 0:10:27It's probably the largest piece of rotating equipment
0:10:27 > 0:10:29that I'll be involved in in my career!
0:10:29 > 0:10:31Just the scale of it all, it just plays back to everything
0:10:31 > 0:10:34I really was interested in in getting into this career -
0:10:34 > 0:10:37playing with big boys toys. And it doesn't get any bigger than this.
0:10:41 > 0:10:46This is Mary - a gigantic tunnel boring machine.
0:10:47 > 0:10:50She cost £11 million
0:10:50 > 0:10:53and is specially designed to dig under the River Thames.
0:10:55 > 0:10:58Boring under the Thames, it really is high risk,
0:10:58 > 0:11:01but it's all about really knowing the ground conditions
0:11:01 > 0:11:04and making sure you select the best equipment on the market
0:11:04 > 0:11:07and this, this is world-class.
0:11:07 > 0:11:11It's like a thousand-tonne factory that will go under the Thames.
0:11:16 > 0:11:20The tunnel boring machine, or TBM, has sharp cutters
0:11:20 > 0:11:24in a huge rotating wheel that scrape at the earth like a drill.
0:11:26 > 0:11:31Behind this cutterhead, an enclosed steel cage supports the earth
0:11:31 > 0:11:35and creates a safe area for miners to build a concrete ring.
0:11:35 > 0:11:38Seven pre-cast segments make up each ring.
0:11:38 > 0:11:41A wedge-shaped keystone locks them in place.
0:11:46 > 0:11:48Once a ring is complete,
0:11:48 > 0:11:51hydraulic rams push the machine further forward into the ground.
0:11:54 > 0:11:58Every metre and a half they advance, they can build another ring.
0:12:00 > 0:12:06In perfect conditions, this digging demon can build up to 18 rings a day
0:12:06 > 0:12:10leaving a water-tight, tube-shaped train tunnel in its wake.
0:12:12 > 0:12:16This is designed really to do, at long average, 27 metres a day.
0:12:16 > 0:12:19We hope, generally, on average allowing for maintenance,
0:12:19 > 0:12:21we're doing 100 metres a week.
0:12:23 > 0:12:26Mary's cutterhead is over seven metres across,
0:12:26 > 0:12:30so that she can dig a tunnel wide enough for the new trains.
0:12:32 > 0:12:34Her teeth are made of tungsten carbide -
0:12:34 > 0:12:37tough enough to scrape away the chalks and flints.
0:12:41 > 0:12:44Once underground, a crew of highly-skilled workers
0:12:44 > 0:12:47will keep Mary running 24 hours a day.
0:12:49 > 0:12:51You know, there's 60 men who'll work on these machines.
0:12:51 > 0:12:54The crews that run these are a very close-knit group
0:12:54 > 0:12:56who've all worked together before.
0:12:56 > 0:12:58These tunnellers do it for their whole careers.
0:12:59 > 0:13:03So it's still a very kinda like manual process, isn't it?
0:13:03 > 0:13:04Even though it's all automated,
0:13:04 > 0:13:07- you're still relying on the skill of the operator.- Absolutely.
0:13:07 > 0:13:11The responsibility of the operator is... It's on a high level.
0:13:12 > 0:13:15Mary's cutterhead will dig through several areas
0:13:15 > 0:13:17of high water pressure under the Thames.
0:13:21 > 0:13:24If any of her tungsten carbide teeth break,
0:13:24 > 0:13:28workers will have to pass through an airlocked chamber to repair them.
0:13:28 > 0:13:31- So it's like a submarine that goes underground.- Yeah.
0:13:31 > 0:13:35- It's this type of a thing.- Should paint it...should paint it yellow!
0:13:35 > 0:13:36- Yeah!- Yeah! - GUS LAUGHS
0:13:36 > 0:13:38Very good, yeah!
0:13:40 > 0:13:42Mary is one of eight tunnel digging machines
0:13:42 > 0:13:45being built at this factory for the Crossrail project.
0:13:46 > 0:13:50Each one is shipped to London, like a giant jigsaw puzzle,
0:13:50 > 0:13:52in more than 50 pieces.
0:13:57 > 0:14:01Workers must re-assemble these kits before digging can begin.
0:14:05 > 0:14:09At this worksite just east of Canary Wharf, a team is preparing
0:14:09 > 0:14:13to put the most critical piece of this tunnelling machine in place.
0:14:16 > 0:14:19They must lift the enormous cutting wheel
0:14:19 > 0:14:22and connect it to the rest of the machine.
0:14:26 > 0:14:28Lift manager, Lee Bartley, is on site
0:14:28 > 0:14:31- to make sure nothing goes wrong. - SHOUTING
0:14:31 > 0:14:35The TBM itself is made up of many, many, er, different bits and we've,
0:14:35 > 0:14:38we've, er...had to sort of put together about,
0:14:38 > 0:14:43something in the region of, er, 70, 80 pieces to get to that stage now.
0:14:43 > 0:14:45This is the essential part of the tunnel boring machine.
0:14:45 > 0:14:48This is the face, what does the actual tunnelling process.
0:14:48 > 0:14:51Without this, it's nothing. It is vital that this is right.
0:14:53 > 0:14:56The cutterhead weighs 62 tonnes
0:14:56 > 0:14:59and needs two cranes to raise it up into place.
0:14:59 > 0:15:01It's critical their movements are in sync
0:15:01 > 0:15:04or the heavy load could swing out of control.
0:15:04 > 0:15:08- WOMAN: OK, he's coming down a touch. - Stop!- Stop!- Stop!
0:15:08 > 0:15:11Commanding the operators is banksman Clare Hallewell.
0:15:11 > 0:15:15'I was in the armed forces for 7½ years, so, erm,'
0:15:15 > 0:15:18this is pretty much similar to what I used to do.
0:15:18 > 0:15:19We used to build bridges
0:15:19 > 0:15:23'and go in the back of tanks. We're used to dealing with big lifts.'
0:15:23 > 0:15:25OK, ready.
0:15:30 > 0:15:32Just take it up that angle and then....
0:15:32 > 0:15:36- Paul can track back, he can jib back and take the weight as well.- OK.
0:15:41 > 0:15:43Look, they're just doing their own thing here.
0:15:43 > 0:15:46Stop 'em both and then, go and talk to 'em both
0:15:46 > 0:15:48and so they're clear with what you want to do.
0:16:03 > 0:16:04MAN: Stop!
0:16:04 > 0:16:06Stop.
0:16:11 > 0:16:13TIMBER CRACKS LOUDLY
0:16:17 > 0:16:19TIMBER CRUNCHES
0:16:51 > 0:16:53OK, stop there.
0:16:59 > 0:17:00- MEN SHOUT: - OK!- OK.
0:17:00 > 0:17:04SHOUTING CONTINUES, INAUDIBLE SPEECH
0:17:08 > 0:17:10- LEE:- Finally in now, and they're all bolted up,
0:17:10 > 0:17:14so, very pleased to say yes, another one in and successful.
0:17:14 > 0:17:15Woo-hoo!
0:17:18 > 0:17:21Crossrail have christened all eight of their tunnel boring machines
0:17:21 > 0:17:24with women's names, like ships.
0:17:24 > 0:17:28This one is called Elizabeth, after the Queen.
0:17:29 > 0:17:34The team "launches" Elizabeth by lowering her down a 35-metre hole.
0:17:36 > 0:17:40From here, she will begin an epic underground voyage to Farringdon.
0:17:45 > 0:17:46Her first port of call
0:17:46 > 0:17:50will be the newly-constructed station at Canary Wharf.
0:17:56 > 0:17:58One stop east back at the Royal Docks...
0:18:03 > 0:18:07- Thank you very much.- ..Linda and structural engineer David Wilde
0:18:07 > 0:18:10are doing further research on the new plan
0:18:10 > 0:18:13to seal off the waterway above the Connaught Tunnel
0:18:13 > 0:18:15so they can rebuild it from the top down.
0:18:16 > 0:18:19The original engineers' drawings of the tunnel
0:18:19 > 0:18:22are held in the archives at the Museum of London Docklands.
0:18:23 > 0:18:26So there it is, there's the Victoria Dock.
0:18:26 > 0:18:29This is going to be the Albert Dock when it's done, isn't it?
0:18:29 > 0:18:32But at this time, it's actually called "proposed extension",
0:18:32 > 0:18:35cos they haven't actually decided on a name for it.
0:18:37 > 0:18:39I have to say, I've never started a job
0:18:39 > 0:18:43- where I've had to go back and look at, er...- The drawings.
0:18:43 > 0:18:45- ..the original drawings. - DAVID LAUGHS
0:18:45 > 0:18:47- 135-year-old drawings there.- Yeah.
0:18:47 > 0:18:50We've been presented with the same problems
0:18:50 > 0:18:51as the original construction.
0:18:51 > 0:18:54Basically, a lot of it's to do with water,
0:18:54 > 0:18:59and how you actually build something with all the water around it.
0:19:00 > 0:19:02Linda and David are encouraged to see that
0:19:02 > 0:19:06their new plan for rebuilding the tunnel mirrors the techniques
0:19:06 > 0:19:08used by the engineers who originally built it.
0:19:10 > 0:19:14"Existing dam" - see that's history repeating itself there.
0:19:14 > 0:19:17This one is good in so far as I believe it shows the open cut.
0:19:17 > 0:19:21- Mmm.- The way it was excavated and installed in the first instance.
0:19:21 > 0:19:22What they would have done is,
0:19:22 > 0:19:25instead of tunnelling underneath the ground,
0:19:25 > 0:19:29they've actually excavated around the profile,
0:19:29 > 0:19:31and then installed the tunnel in there.
0:19:31 > 0:19:34So they've built it from the top downwards, effectively.
0:19:35 > 0:19:37The plan was that we were going
0:19:37 > 0:19:40to enlarge the Connaught Tunnel from within. And we were never
0:19:40 > 0:19:45going to need to put cofferdams down and block off the passageway.
0:19:45 > 0:19:48But now, on reflection and looking back at these drawings,
0:19:48 > 0:19:51and looking at the two twin-walled cofferdams standing there
0:19:51 > 0:19:57with 1872, 1874 written in the corner of the drawings, I...
0:19:57 > 0:19:59I think it was meant to be!
0:20:03 > 0:20:06The London Boat Show is now over.
0:20:06 > 0:20:09As the last luxury yachts cruise out of the docks,
0:20:09 > 0:20:13the narrow window of opportunity opens for Linda's team.
0:20:15 > 0:20:18They can now close the passage directly above the tunnel.
0:20:19 > 0:20:22They must reopen it again in time for navy ships
0:20:22 > 0:20:25to get to the Defence Show in just seven months' time.
0:20:27 > 0:20:30Working with ExCel to try and fit this in between
0:20:30 > 0:20:33their London Boat Show and the Defence Show coming in September,
0:20:33 > 0:20:37we'll try and quickly get in here, do open heart surgery on this tunnel
0:20:37 > 0:20:41from the top, rebuild it into a larger tunnel
0:20:41 > 0:20:43and get out of here by the time the Defence Show comes.
0:20:43 > 0:20:45It's hard work.
0:20:46 > 0:20:50With the clock ticking, Linda's team wastes no time draining the water.
0:20:52 > 0:20:56As they pump the last drops out, a specialist team moves in.
0:20:57 > 0:20:59Well, we're here today really, er,
0:20:59 > 0:21:01just as part of the welfare.
0:21:01 > 0:21:04Obviously, there could be some fish trapped in between the cofferdams
0:21:04 > 0:21:07and there's an opportunity arised whereby
0:21:07 > 0:21:10the water's at a level where we can sweep round with a seine net
0:21:10 > 0:21:14and basically see if there's anything in there that needs rescuing.
0:21:14 > 0:21:17Years ago, this river used to have salmon, sea trout,
0:21:17 > 0:21:19sturgeon running through it.
0:21:19 > 0:21:22There is always a possibility, with the water getting cleaner,
0:21:22 > 0:21:24that those fish could have come back.
0:21:24 > 0:21:27You might pick something up strange like that in here,
0:21:27 > 0:21:28so, er, you never say never.
0:21:32 > 0:21:34That's is as low as it's going to go, I think.
0:21:34 > 0:21:36I'm going to go down in the cage with it,
0:21:36 > 0:21:37cos I think it'll be easier to get out.
0:21:37 > 0:21:39- I'll meet you at the bottom of the steps.- OK.
0:21:41 > 0:21:42It opens inwards!
0:21:45 > 0:21:49- Ready?- Yup.- Are you going to get in?- I will do once you're in.
0:21:49 > 0:21:51Whoa, whoa, whoa!
0:21:55 > 0:21:57- That's a baby mullet, innit?- Yeah.
0:22:01 > 0:22:03Ooh...
0:22:03 > 0:22:06Unfortunately, we've got lots of muck and debris.
0:22:08 > 0:22:11Well, there's a handful of small...small fish.
0:22:14 > 0:22:16HE GRUNTS
0:22:18 > 0:22:19We haven't got many there,
0:22:19 > 0:22:22cos a lot of them were these real small fellas here,
0:22:22 > 0:22:27which went through the net, and they're a type of scad.
0:22:30 > 0:22:33Then we've got...a sprat.
0:22:33 > 0:22:37I think that's juvenile bass,
0:22:37 > 0:22:41which will grow up to the sea bass that you find in the restaurants.
0:22:41 > 0:22:44And then, somewhere in here, we've got a young...
0:22:44 > 0:22:48a baby young bronze bream, which is called a skimmer.
0:22:48 > 0:22:52They release the rescued fish into the open dock.
0:22:53 > 0:22:55They should be happy in their new home now.
0:22:57 > 0:22:58So away they go.
0:23:13 > 0:23:15South of the river near Woolwich...
0:23:15 > 0:23:18HORN BLASTS
0:23:18 > 0:23:21..Gus's team is putting together the giant jigsaw puzzle
0:23:21 > 0:23:24that has arrived from Germany.
0:23:24 > 0:23:28Mary, the £11 million tunnelling machine
0:23:28 > 0:23:30that will dig Crossrail's new Thames tunnel.
0:23:30 > 0:23:33The big thing is how huge these bits are, you know, the...
0:23:33 > 0:23:3840 tonnes, 35 tonnes here, 10-tonne, 15-tonne bits
0:23:38 > 0:23:41all bolt together to make this 1,000-tonne factory.
0:23:42 > 0:23:46The team will guide Mary north under the river from here.
0:23:46 > 0:23:48CHEERING
0:23:49 > 0:23:51Everyone's chomping at the bit to get her going
0:23:51 > 0:23:53and she is a beautiful machine, she is.
0:23:55 > 0:23:57On the team is Peter Bermingham.
0:23:57 > 0:24:01He's been tunnelling for 50 years and turns 70 today.
0:24:01 > 0:24:02APPLAUSE
0:24:07 > 0:24:10Thank you very much. That's it. Help yourselves, please.
0:24:11 > 0:24:13Digging Crossrail's Thames tunnel
0:24:13 > 0:24:16will be Peter's final project before retiring.
0:24:18 > 0:24:20Peter's two sons, Dan and Robert,
0:24:20 > 0:24:22are working shoulder to shoulder with their dad
0:24:22 > 0:24:24building the Crossrail tunnels.
0:24:24 > 0:24:26I've spent three minutes of my life making him,
0:24:26 > 0:24:28and I've spent three minutes of my life making him.
0:24:28 > 0:24:30SOME LAUGHTER Yeah, Mum doesn't...
0:24:30 > 0:24:32Mum doesn't reckon it wasn't that long, really!
0:24:32 > 0:24:34LAUGHTER
0:24:34 > 0:24:37There's been three really significant tunnelling projects.
0:24:37 > 0:24:40There's been the Channel Tunnel, the Jubilee Line extension,
0:24:40 > 0:24:43and now Crossrail and he's been sort of, like, intricately involved
0:24:43 > 0:24:46in all three of those, you know, that's a hell of a thing to leave.
0:24:48 > 0:24:51When these new tunnels are finished,
0:24:51 > 0:24:54Peter will have tunnelled under the Thames ten times.
0:24:54 > 0:24:57I don't think anybody in history's done that and
0:24:57 > 0:24:59it'll be a long time before anybody else does.
0:24:59 > 0:25:01The son of Irish immigrants, you know, you were a "navvie"
0:25:01 > 0:25:05and, er, this is a "navvie" becoming a highly-respected professional.
0:25:09 > 0:25:10What have we got here?
0:25:12 > 0:25:16Tunnelling was very different when Peter first started out.
0:25:16 > 0:25:19I first started tunnelling in 1964, on the Victoria Line.
0:25:21 > 0:25:24A hand-driven tunnel, bored by hand.
0:25:24 > 0:25:28We wore cloth caps, no helmets or protective clothing at that time.
0:25:28 > 0:25:31The machinery wasn't that powerful. Most of it was hand tools.
0:25:31 > 0:25:34I cannot believe it was in my time. It looked like
0:25:34 > 0:25:37walking back on Victorian times, you know. We've come so far.
0:25:37 > 0:25:40With the equipment we've got down there now, absolutely fantastic.
0:25:51 > 0:25:53There is a special breed of tunnel guys.
0:25:53 > 0:25:55You can't be normal if you go underground, can you?
0:25:55 > 0:25:58I mean, you're living in the bowels of the Earth,
0:25:58 > 0:26:00but, er, it's a proud industry to be in.
0:26:03 > 0:26:06And the technology's come along so much and so fast, you know, to be
0:26:06 > 0:26:10able to go through ground we never thought possible, it's incredible.
0:26:14 > 0:26:17With the cutterhead in place, she's set for launch.
0:26:17 > 0:26:20MEN SHOUTING
0:26:20 > 0:26:23It takes three days to push the 150-metre-long machine
0:26:23 > 0:26:26into the earth on the South Bank of the Thames.
0:26:29 > 0:26:3520 workers, in two shifts, will keep her drilling 24 hours a day
0:26:35 > 0:26:38through one and a half kilometres of boggy ground beneath the river.
0:26:40 > 0:26:41It will take eight months
0:26:41 > 0:26:44for the machine to resurface on the other side.
0:26:54 > 0:26:56One stop west at the Royal Docks...
0:26:59 > 0:27:01..Linda's team has no time to lose.
0:27:01 > 0:27:03They have drained the dock,
0:27:03 > 0:27:05exposing the roof of the old Connaught Tunnel.
0:27:07 > 0:27:11They now have just six months left to completely rebuild this tunnel,
0:27:11 > 0:27:15re-flood the dock and reopen this passageway for ships.
0:27:16 > 0:27:19We've got, um, we've got lots of work fronts going on,
0:27:19 > 0:27:22so we're working in the tunnel, working in the dock.
0:27:22 > 0:27:25We're all a team, basically, working together trying to achieve one goal.
0:27:26 > 0:27:29The team must complete a laundry list of challenges
0:27:29 > 0:27:30in a very short time.
0:27:33 > 0:27:37First task - remove the steel rings lining the twin tunnel section.
0:27:37 > 0:27:41Then knock down the connecting wall to create
0:27:41 > 0:27:44a single, bigger passageway for Crossrail trains to run through.
0:27:45 > 0:27:49What you can see quite clearly here, now that the docks are empty,
0:27:49 > 0:27:51you can see the cast steel barrel.
0:27:53 > 0:27:56The Crossrail tunnel is going to be wider and rectangular
0:27:56 > 0:28:00and fit its haunches within the old tunnel.
0:28:04 > 0:28:07The team makes good progress removing the rings.
0:28:10 > 0:28:12But as they cut the steel away in this corner,
0:28:12 > 0:28:16they reveal a completely unexpected brick arch behind.
0:28:18 > 0:28:20That's the problem.
0:28:20 > 0:28:23The new tunnel is supposed to fit inside this arch.
0:28:23 > 0:28:26But it hangs too low for the new tunnel to fit in.
0:28:28 > 0:28:30That's got to be removed.
0:28:33 > 0:28:36Linda and the team can't just remove the arch,
0:28:36 > 0:28:39because it could be supporting the docks above.
0:28:44 > 0:28:47You're not going to be able to take a section out of this
0:28:47 > 0:28:50and still be able to hold onto your arching effect.
0:28:50 > 0:28:52- Very unlikely.- Unlikely.
0:28:52 > 0:28:55- Is it the same on the other side? - Yeah, but we don't know how far.
0:28:55 > 0:28:59All the rings they've taken out so far, we've got the reduced dimension.
0:28:59 > 0:29:02All right. Yeah.
0:29:02 > 0:29:06So, this is yet another time when this tunnel shows us new mysteries.
0:29:06 > 0:29:08This job actually started construction
0:29:08 > 0:29:13a year ahead of when everyone said that it needed to.
0:29:13 > 0:29:15And it was because a predecessor of mine said,
0:29:15 > 0:29:18"It's going to be a bucket of spiders."
0:29:18 > 0:29:21And, oh, my goodness! Have we used every bit of that?
0:29:21 > 0:29:23And now we're staring at the end date
0:29:23 > 0:29:26that we never thought that we would need to be worried about.
0:29:28 > 0:29:31Linda and the team are already facing a very tight deadline.
0:29:31 > 0:29:34They can't afford this new delay.
0:29:34 > 0:29:37They need to find out as quickly as possible if the arch is
0:29:37 > 0:29:41holding the docks above or if it's safe for them to remove it.
0:29:43 > 0:29:46Somebody's going to get Central Engineering to start having a look,
0:29:46 > 0:29:48the Chief Geotech, and I want them to hear about it now
0:29:48 > 0:29:52so when they show up at the meeting on Friday they will already have had
0:29:52 > 0:29:55a chance to think it through, maybe look up some information on it
0:29:55 > 0:29:57to either say it's going to work or it's not going to work.
0:30:03 > 0:30:05One stop east at Woolwich...
0:30:08 > 0:30:09..the Thames tunnelling machine
0:30:09 > 0:30:12has started burrowing her way underneath the river.
0:30:12 > 0:30:14MEN SHOUT
0:30:17 > 0:30:20Engineers have locked the first few hundred concrete panels
0:30:20 > 0:30:22that form the walls of the tunnel in place.
0:30:24 > 0:30:26They have over a thousand more to go.
0:30:28 > 0:30:31It is hard to get lost down here, cos there's only one way in and out,
0:30:31 > 0:30:33but I tell you something, if the lights went off
0:30:33 > 0:30:36and it was pitch black, you'd have a hard time finding your way about.
0:30:37 > 0:30:41At key points, Dan's team needs to drill through the panels
0:30:41 > 0:30:43to create cross passages,
0:30:43 > 0:30:46connecting the east- and west-bound train tunnels together.
0:30:48 > 0:30:50We're literally going to break these out.
0:30:50 > 0:30:55We'll, obviously, stitch drill around the area where it needs to,
0:30:55 > 0:30:58then break it out and have a back hoe digging out
0:30:58 > 0:31:00and sprayed concrete lining inside.
0:31:01 > 0:31:04The panels hold back huge amounts of ground water.
0:31:08 > 0:31:12The team must battle this water before they drill through them.
0:31:14 > 0:31:17We've got 2½ bar water pressure behind us at this point,
0:31:17 > 0:31:19so we need to grout the ground behind
0:31:19 > 0:31:22to seal off any water before we open up.
0:31:25 > 0:31:29These things here are valves and, obviously, we'll pump grout through
0:31:29 > 0:31:32these valves behind the back of the ring and into the open ground.
0:31:36 > 0:31:40This water is surrounding the whole tunnel all the way up and through.
0:31:40 > 0:31:43You can try and de-water it, but there's so much, it'll take forever.
0:31:43 > 0:31:47So what we do is just seal up the fissures in the ground,
0:31:47 > 0:31:50and push it away from the area that we're going to tunnel through.
0:31:52 > 0:31:53It's a great challenge.
0:32:00 > 0:32:01Tunnelling under the Thames
0:32:01 > 0:32:04has been a Great British obsession for hundreds of years.
0:32:07 > 0:32:10The first tunnel ever built beneath a river anywhere in the world
0:32:10 > 0:32:13was the Thames Tunnel built by Marc Brunel
0:32:13 > 0:32:15and his son Isambard Kingdom Brunel.
0:32:18 > 0:32:20This tunnel was a twin-track passage,
0:32:20 > 0:32:22designed for horse-drawn vehicles.
0:32:27 > 0:32:30It still exists today and carries rail traffic.
0:32:32 > 0:32:35To build it, Marc Brunel designed a revolutionary invention.
0:32:37 > 0:32:41Called a tunnel shield, it was an iron cage protecting 36 miners
0:32:41 > 0:32:45excavating clay by hand at the digging face.
0:32:45 > 0:32:46DIGGING AND SCRAPING
0:32:49 > 0:32:53As the men dug further, enormous screws inched the structure forward.
0:32:53 > 0:32:55STRAINING AND SQUEAKING
0:32:55 > 0:32:59Behind, bricklayers shored up the exposed tunnel walls.
0:32:59 > 0:33:01SCRAPING AND TAPPING
0:33:01 > 0:33:04Two shifts of men drove the tunnel forward 16 hours a day.
0:33:04 > 0:33:07SCRAPING AND STRAINING CONTINUES
0:33:07 > 0:33:11It took them 16 years to dig from one bank to the other -
0:33:11 > 0:33:13a distance of just a quarter of a mile.
0:33:17 > 0:33:20Brunel's Thames Tunnel opened in 1843,
0:33:20 > 0:33:22initially as a pedestrian walkway.
0:33:22 > 0:33:25BUZZ OF CONVERSATION
0:33:25 > 0:33:29More than one million people, half the population of London,
0:33:29 > 0:33:31visited this subterranean wonder
0:33:31 > 0:33:33within the first three months of its opening.
0:33:36 > 0:33:38A modified version of Brunel's shield
0:33:38 > 0:33:41was later used to excavate the London Underground.
0:33:44 > 0:33:48Today, the machines digging Crossrail's Thames tunnels
0:33:48 > 0:33:50are souped up versions of his design.
0:33:52 > 0:33:53TBMs have been around...
0:33:53 > 0:33:56Well, Isambard Kingdom Brunel's dad invented them didn't he, really?
0:33:56 > 0:34:00The first shields, the hand shields, and it's just advanced from there.
0:34:02 > 0:34:05It's very difficult to tunnel through here.
0:34:05 > 0:34:07Every time you go under, technology makes it
0:34:07 > 0:34:10just that bit easier, it always moves on.
0:34:10 > 0:34:12- Go?- That's it, go.
0:34:12 > 0:34:15But you do have a lot of heavy kit in close quarters.
0:34:15 > 0:34:18MACHINERY WHIRRS
0:34:18 > 0:34:21There's no such thing as a small hurt. If you make a mistake on here,
0:34:21 > 0:34:23there's no such thing as a small error.
0:34:23 > 0:34:26The impact is quite severe, so you've got to get it right, yeah.
0:34:26 > 0:34:29It takes the driver and miner less than an hour
0:34:29 > 0:34:32to install each of the concrete rings that keep the water at bay.
0:34:37 > 0:34:40Pipes and pumps suck the clay slurry
0:34:40 > 0:34:42away from the digging face as they advance.
0:34:42 > 0:34:44DRILLING, MEN SHOUT
0:34:44 > 0:34:48We mark every ring, and number it based on...
0:34:48 > 0:34:50The first ring of the tunnel is ring number one.
0:34:50 > 0:34:56This is actually 1,232, but on that ring, I managed to drop the number,
0:34:56 > 0:34:58so it's under the segment feeder somewhere.
0:34:58 > 0:35:01It'll come out the back, it's no problem,
0:35:01 > 0:35:04but I don't know whether I should improvise a number one or...
0:35:08 > 0:35:12That's a convincing number 1, I think. That'll do me.
0:35:14 > 0:35:16Maybe this is just pride of project or whatever,
0:35:16 > 0:35:19but out of all the projects, this is one I prefer to be on.
0:35:19 > 0:35:21You know, it's the most unique.
0:35:22 > 0:35:25And, er, we're going under the river,
0:35:25 > 0:35:28so there's a bit of a pride about it, so there is.
0:35:30 > 0:35:34A rubber seal surrounds each concrete panel.
0:35:34 > 0:35:38The crew must check the seals for punctures, and grease them,
0:35:38 > 0:35:39before bolting the panels together
0:35:39 > 0:35:43to make sure the tunnel walls are watertight.
0:35:43 > 0:35:46Basically, this whole tunnel, we were mining under the water table.
0:35:46 > 0:35:51We never mine above water and we're in water-bearing strata as well,
0:35:51 > 0:35:54so it's all around us right now. But the sealing systems of the ring
0:35:54 > 0:35:57and the design of the ring means that we keep it out.
0:35:59 > 0:36:02The final layer of protection - a foam band
0:36:02 > 0:36:05that will expand on contact with water to block any leaks.
0:36:08 > 0:36:14Even with all this technology, no tunnel is ever 100% watertight.
0:36:16 > 0:36:19We've got a little bit of water coming through there.
0:36:19 > 0:36:21If there's nothing there to stop that coming through,
0:36:21 > 0:36:23obviously, we would have a very wet tunnel.
0:36:23 > 0:36:27Yeah, we'll need to keep an eye on it, because, if it gets any worse,
0:36:27 > 0:36:30we'll make sure we can come back and repair it,
0:36:30 > 0:36:32we know exactly where it's at
0:36:32 > 0:36:34and do any remedial works that are necessary.
0:36:41 > 0:36:44Millions of people will be doing this in a couple of years' time.
0:36:44 > 0:36:47I just hope it's a bit less noisy and a bit less bumpy.
0:36:54 > 0:36:59That's our work done for the day. I've been in to see the lads.
0:36:59 > 0:37:01These guys are going to carry on a few hours.
0:37:01 > 0:37:03It's my last shift here, so...
0:37:03 > 0:37:06I'm on my way home now up to sunny North Wales.
0:37:11 > 0:37:14North of the river at the Connaught Tunnel...
0:37:17 > 0:37:19..Linda's team is back on track.
0:37:20 > 0:37:23Their survey revealed that the passageway's brickwork
0:37:23 > 0:37:26is strong enough for them to remove this low arch
0:37:26 > 0:37:28without risk of the whole tunnel caving in.
0:37:30 > 0:37:34In fact, Linda has discovered that the brickwork is unusually strong.
0:37:35 > 0:37:40The mortar between them is 100% full. There's no gaps here at all.
0:37:40 > 0:37:43It's a fantastic, fantastic job.
0:37:43 > 0:37:48And then, the 135 years of earth pressure and water against it
0:37:48 > 0:37:52has sealed it up to where it's behaving more like stainless steel
0:37:52 > 0:37:54than it is brick and mortar.
0:37:55 > 0:37:58The strong mortar is now causing the latest problem for the team...
0:37:58 > 0:38:00DRILLING
0:38:00 > 0:38:02..they can't get the bricks out quickly enough.
0:38:03 > 0:38:05So just over a third of the way to go, but, er...
0:38:05 > 0:38:08it's quite slow going, this brickwork.
0:38:08 > 0:38:10You know, I've seen brickwork like this taken down
0:38:10 > 0:38:14and all you normally need to do is have a couple of stabs at the mortar
0:38:14 > 0:38:15and that whole brick layer goes off.
0:38:15 > 0:38:19- A couple more stabs at the mortar, the next layer goes off.- Yeah.
0:38:19 > 0:38:21I know the men are taking a short break here now,
0:38:21 > 0:38:24but hand breaking out this 130-year-old brick
0:38:24 > 0:38:27- is just, well, it's just hard work. - Yeah, it's going to take a while.
0:38:27 > 0:38:29I know they're working it night and day,
0:38:29 > 0:38:32- I know they've got extra crews in, but there's not much time.- Yeah.
0:38:32 > 0:38:37Linda's crew has just two weeks left before they must reflood the dock.
0:38:37 > 0:38:39They are behind schedule.
0:38:40 > 0:38:43Here we are in the last throes of the last couple of weeks
0:38:43 > 0:38:45before we put the water back in.
0:38:45 > 0:38:47We couldn't be throwing more into it than this.
0:38:51 > 0:38:54We're all doing shifts, covering each other, and just doing
0:38:54 > 0:38:57everything we can to get it all done by our deadline date next weekend.
0:38:57 > 0:39:00September 2nd is not that far away.
0:39:00 > 0:39:02And we're going to see military ships
0:39:02 > 0:39:06that are going to be looking at us over our cofferdams
0:39:06 > 0:39:08unless we get out of the water.
0:39:18 > 0:39:22Underneath the river at Woolwich, the Thames tunnel boring machine
0:39:22 > 0:39:25is nearly halfway through her long drive to the northern bank.
0:39:25 > 0:39:28DRILLING AND RATTLING
0:39:28 > 0:39:31Each six metres the tunnel advances,
0:39:31 > 0:39:35the crew must extend the rails for locomotives,
0:39:35 > 0:39:38and the pipes that carry the waste away from the digging face.
0:39:44 > 0:39:48A team of nine, working seven days on and four days off,
0:39:48 > 0:39:50keep the machine moving.
0:39:50 > 0:39:54It's hard work, but it's an entry into a tunnelling career.
0:40:09 > 0:40:13No matter how hard they work, the team and tunnelling machine
0:40:13 > 0:40:15can only advance as fast as the chalk and flint
0:40:15 > 0:40:17is removed from the tunnel face.
0:40:19 > 0:40:23A 3km long network of pipes, snaking under London,
0:40:23 > 0:40:27transports the clay and slurry to this plant in Plumstead.
0:40:27 > 0:40:31If this facility goes down, tunnelling grinds to a halt.
0:40:32 > 0:40:38This humble-looking shed houses the pinch point of the entire operation.
0:40:38 > 0:40:41Whatever we excavate, the chalk, sands and gravels
0:40:41 > 0:40:43all get pumped back in slurry through this pipe.
0:40:45 > 0:40:50We take out all the larger particles through the trommel,
0:40:50 > 0:40:55through the de-sanding unit, through the de-silting unit,
0:40:55 > 0:40:57and then the waste slurry.
0:40:57 > 0:41:00Everything that hasn't got anything over about half a millimetre
0:41:00 > 0:41:05gets stored in a huge tank outside, and then we pump it over into
0:41:05 > 0:41:06this room, the filter press room,
0:41:06 > 0:41:08where we've got six of these presses.
0:41:10 > 0:41:13The principle behind it is very simple.
0:41:13 > 0:41:17Basically, to hold the slurry so you can squeeze the moisture out,
0:41:17 > 0:41:19recycle the water and be left with the cakes.
0:41:23 > 0:41:26I guess in a way the simple things are the best ideas.
0:41:28 > 0:41:30We can do 40, 50 tonnes an hour here.
0:41:32 > 0:41:35Gus' team ships the cakes to Essex
0:41:35 > 0:41:39where they are used to nourish grassland conservation areas.
0:41:39 > 0:41:42And this really controls the advance rate of the TBM.
0:41:42 > 0:41:45If we can't get the materials out quick enough then we can't advance.
0:41:52 > 0:41:57Two stops west, the tunnel-boring machine called Elizabeth
0:41:57 > 0:41:59is homing in on Canary Wharf.
0:42:00 > 0:42:05Elizabeth has tunnelled nearly 2km through solid ground
0:42:05 > 0:42:09and must now hit a target, the newly-built station box,
0:42:09 > 0:42:12with millimetre precision.
0:42:12 > 0:42:14We're at the minus six level of the Canary Wharf box
0:42:14 > 0:42:18and we're just waiting on our first TBM to pop its head through
0:42:18 > 0:42:19for our first breakthrough.
0:42:22 > 0:42:27This is our first breakthrough on an existing structure, so for us
0:42:27 > 0:42:31this is all about making sure that the machine is where it should be.
0:42:34 > 0:42:38Canary Wharf station is a giant six-level box,
0:42:38 > 0:42:45with a garden, shops and restaurants on the upper floors...
0:42:45 > 0:42:47and the platforms deep below ground.
0:42:49 > 0:42:52Peter Main's team must drive their tunnel-boring machine through
0:42:52 > 0:42:56the station's concrete walls, hitting a specially-designed target.
0:43:01 > 0:43:04You do a lot of hard work on it and one little hiccup,
0:43:04 > 0:43:07it's only one decimal point you need to be out,
0:43:07 > 0:43:09and it could be metres off.
0:43:19 > 0:43:21On the other side of the station wall,
0:43:21 > 0:43:24the tunnelling crew put the final rings in place.
0:43:27 > 0:43:32In charge is Scott Moss - one of almost 200 young graduate engineers
0:43:32 > 0:43:35hoping to follow in Brunel's footsteps,
0:43:35 > 0:43:38and join in the Great British burrowing obsession.
0:43:39 > 0:43:40I have to check the rings.
0:43:40 > 0:43:44Make sure all the rings are intact, no damages to them.
0:43:44 > 0:43:47If it wasn't for the segments, there wouldn't be a tunnel wall,
0:43:47 > 0:43:50so they are quite important in that respect.
0:43:50 > 0:43:52It's really important that the segments get laid out
0:43:52 > 0:43:55in the right sequence. As we are excavating,
0:43:55 > 0:43:58I decide what orientation the next ring gets installed at.
0:44:00 > 0:44:02I only started at the beginning of March,
0:44:02 > 0:44:04so only two and a half months.
0:44:04 > 0:44:06So all is extremely new to me.
0:44:09 > 0:44:11I just hope I don't give them the wrong ring.
0:44:19 > 0:44:24A tunneller's first breakthrough is an important rite of passage.
0:44:24 > 0:44:26It's the highlight of the job.
0:44:26 > 0:44:28Not only is it my first breakthrough, it's this project's
0:44:28 > 0:44:32first breakthrough as well. It's a massive occasion
0:44:32 > 0:44:34and we're just all hoping it all goes well
0:44:34 > 0:44:37and we turn up at the right place at Canary Wharf.
0:44:44 > 0:44:47The noise you can hear is Elizabeth, our first TBM.
0:44:47 > 0:44:51She's currently boring her way through the concrete that'll
0:44:51 > 0:44:53bring her in to the Canary Wharf box.
0:45:03 > 0:45:07But with less than a metre to go, Elizabeth stops digging.
0:45:19 > 0:45:21CAMERON: How bad is it?
0:45:23 > 0:45:26There could be a dozen reasons for stopping cutting, you know?
0:45:26 > 0:45:28It could be a belt issue, but we'll find out.
0:45:32 > 0:45:35Elizabeth has a conveyor belt stretching all the way up to
0:45:35 > 0:45:39the surface to carry away the excavated rock and soil.
0:45:39 > 0:45:40Today, of all days,
0:45:40 > 0:45:45this crucial link has broken - the belt has slipped.
0:45:45 > 0:45:47Elizabeth can't break through until it's fixed.
0:45:51 > 0:45:53Scott's shift is about to end.
0:45:53 > 0:45:56There will be no first breakthrough for the young engineer.
0:45:56 > 0:46:00The night shift get to claim the first breakthrough of this contract.
0:46:00 > 0:46:01Devastated, to be honest.
0:46:05 > 0:46:08They work into the night trying to fix the belt
0:46:08 > 0:46:09on the other side of the wall.
0:46:12 > 0:46:15Can't do anything more about it now. Just wait patiently.
0:46:15 > 0:46:16Or impatiently.
0:46:18 > 0:46:22We're going to repair the conveyor for the rest of this night shift,
0:46:22 > 0:46:25and then we'll shove through between 7.30 and 8 tomorrow morning.
0:46:45 > 0:46:50The drawn-out fix is good news for Scott, who is now back on shift.
0:46:51 > 0:46:54Unfortunately it took nine hours.
0:46:54 > 0:46:57It's up and running now, so all is well in the end.
0:46:57 > 0:47:00We did the repairs overnight to the conveyor and we're now
0:47:00 > 0:47:02looking forward to Elizabeth coming through.
0:47:02 > 0:47:06Scott's, and Crossrail's, first breakthrough
0:47:06 > 0:47:08is now just centimetres away.
0:47:50 > 0:47:53Scott gets the honour of being second man through.
0:47:59 > 0:48:01I was on the phone to my mum just as we broke through.
0:48:01 > 0:48:04A bit sad, I know, but she was happy for me.
0:48:04 > 0:48:06My very first one.
0:48:06 > 0:48:08They let me come out at the end, one of the first ones,
0:48:08 > 0:48:11so it were brilliant, yeah, I really enjoyed it.
0:48:11 > 0:48:13Ecstatic, totally!
0:48:13 > 0:48:14One, two three...
0:48:14 > 0:48:16THEY CHEER
0:48:17 > 0:48:19One, two, three...
0:48:19 > 0:48:20THEY CHEER
0:48:30 > 0:48:34One stop east at the Royal Docks,
0:48:34 > 0:48:37Linda's team has been working around the clock to remove
0:48:37 > 0:48:40the protruding arch inside the Connaught Tunnel.
0:48:43 > 0:48:46They have just one day left to shore up its roof with steel
0:48:46 > 0:48:48and concrete before they must re-flood this dock.
0:48:50 > 0:48:55This will be the final act of the second part of the play.
0:48:55 > 0:48:58And we're just waiting for the final sign off for the last pour.
0:49:00 > 0:49:04The team had scheduled the concrete pour to start today at dawn.
0:49:04 > 0:49:07But there's a glitch - they need to add more steel
0:49:07 > 0:49:09to strengthen the roof.
0:49:10 > 0:49:146.30 this morning the steel wasn't right. Too narrow.
0:49:14 > 0:49:16So it was a mutual agreed decision to stop.
0:49:18 > 0:49:21This isn't going to work like it is, we need to get some more steel
0:49:21 > 0:49:22in there, some more rebar.
0:49:24 > 0:49:28We're here on the last day pouring concrete on the last minute
0:49:28 > 0:49:29of the last hour.
0:49:32 > 0:49:34And this is a complete departure from the original scheme.
0:50:04 > 0:50:06With the steel finally in place,
0:50:06 > 0:50:09the concrete pour begins - eight hours behind schedule.
0:50:11 > 0:50:14Concrete has just started pumping, unfortunately,
0:50:14 > 0:50:16here at three o'clock in the afternoon rather than
0:50:16 > 0:50:19seven o'clock in the morning. Never a dull moment!
0:50:27 > 0:50:29We've got the concrete pumps
0:50:29 > 0:50:32and they're busy pumping the concrete up through this pipe.
0:50:32 > 0:50:35It comes through here and then it goes up into the outside.
0:50:35 > 0:50:37We had initially planned to do it this morning,
0:50:37 > 0:50:40so it's now this afternoon,
0:50:40 > 0:50:42but now we're finally getting it in and it's almost done.
0:50:45 > 0:50:50The final push pays off and water streams back into the area on time.
0:50:53 > 0:50:56There's one last challenge before boats can pass through here.
0:50:58 > 0:51:01Divers need to cut away the huge steel props that have been
0:51:01 > 0:51:02supporting the dock walls.
0:51:05 > 0:51:06DIVER: OK, ready for main air
0:51:06 > 0:51:10- DIVE SUPERVISOR:- Roger, roger. Main air's coming on to the diver.
0:51:10 > 0:51:12Anything underwater that needs to be done, we're here to
0:51:12 > 0:51:16offer our assistance. It's not easy sort of work.
0:51:16 > 0:51:18You can imagine trying to go down there
0:51:18 > 0:51:19and work in completely black water.
0:51:22 > 0:51:26The divers need to use heat-cutting tools to slice the props free.
0:51:28 > 0:51:31When that's done, they will then start pumping air into the prop,
0:51:31 > 0:51:33which will make it buoyant
0:51:33 > 0:51:35and should enable it to float to the surface.
0:51:35 > 0:51:38It'll be great to see the props come out because that then gives us
0:51:38 > 0:51:41a free passage for when these battleships to come through
0:51:41 > 0:51:42in September.
0:51:43 > 0:51:46We have committed to the Royal Navy,
0:51:46 > 0:51:51and to ExCel that we're going to make this passage free.
0:51:51 > 0:51:55Any time you have divers down in the water, doing hot cutting works,
0:51:55 > 0:52:00it's just by its nature, extremely hazardous, extremely perilous.
0:52:03 > 0:52:04- DIVE SUPERVISOR:- Roger, OK.
0:52:13 > 0:52:16Roger, we'll send down the cutting rig and the rods.
0:52:25 > 0:52:28Yeah, it's hot.
0:52:30 > 0:52:31Make it cold.
0:52:33 > 0:52:35That's cold.
0:52:39 > 0:52:41The air line's ready for you.
0:52:41 > 0:52:42Roger, roger.
0:52:46 > 0:52:48Roger, up on your slack, you're coming back.
0:52:59 > 0:53:02It's been a difficult job but we're getting there.
0:53:10 > 0:53:15One stop east at Woolwich, it's a big day for the Bermingham family.
0:53:15 > 0:53:17They are approaching the last few metres of their drive
0:53:17 > 0:53:19under the Thames.
0:53:19 > 0:53:22So at the moment we're just going to go in to the tunnel
0:53:22 > 0:53:26where TBM 1 is actually still mining underneath the river Thames.
0:53:26 > 0:53:28Nearly reached breakthrough point.
0:53:44 > 0:53:47It took the Brunels 16 years to complete the first Thames tunnel.
0:53:49 > 0:53:53Peter and Dan Bermingham have built theirs in just over eight months.
0:53:57 > 0:54:00We're going to breakthrough into the new reception chamber
0:54:00 > 0:54:04at North Woolwich. We'll be relieved to get through.
0:54:04 > 0:54:07It's always nice to see the light at the end of the tunnel.
0:54:08 > 0:54:12The Thames tunnel machine's cutting wheel is designed to work
0:54:12 > 0:54:14under high pressure when she's digging under water.
0:54:16 > 0:54:18So, just like a diver,
0:54:18 > 0:54:22she must depressurise in a chamber before she can come up for air.
0:54:29 > 0:54:31This is where all the action has been.
0:54:31 > 0:54:35You can see here on the teeth how you've got the wear
0:54:35 > 0:54:38at different levels. That's the full profile,
0:54:38 > 0:54:41and you can see here that's worn all the way back there.
0:54:41 > 0:54:46Been through some tough flints and geology, but er, yeah, made it.
0:54:48 > 0:54:51For lifelong tunneller, Peter Bermingham, completing
0:54:51 > 0:54:55the Crossrail Thames Tunnel is the culmination of a 50-year career.
0:54:55 > 0:54:58No, this is me lot.
0:54:58 > 0:55:00I'm now retiring. Looking forward to that.
0:55:02 > 0:55:04My wife's got a nice little sports car
0:55:04 > 0:55:07so we're talking about driving down the Amalfi coast in Italy.
0:55:07 > 0:55:11Forget about tunnels, concentrate on an enjoyable retirement
0:55:11 > 0:55:14with my wife and grandchildren right now.
0:55:14 > 0:55:15It's good. Time to go.
0:55:23 > 0:55:24Keep hoisting up.
0:55:26 > 0:55:28The tunnel may be finished,
0:55:28 > 0:55:31but this tunnelling machine's life isn't over.
0:55:31 > 0:55:33Try and keep it square to the crane, lads.
0:55:33 > 0:55:36Her components will be re-used to build other tunnels
0:55:36 > 0:55:38around the world.
0:55:38 > 0:55:39Keep coming down.
0:55:42 > 0:55:47Keep coming down. Another 500 mill. Keep lowering off.
0:55:47 > 0:55:50200 mill. Keep coming. Stop.
0:56:02 > 0:56:03At the Royal Docks,
0:56:03 > 0:56:08the waterway above the Connaught Tunnel has finally reopened.
0:56:08 > 0:56:12Linda and the team have completed the tunnel just in the nick of time.
0:56:12 > 0:56:14I can't believe you can see all the way through.
0:56:19 > 0:56:21No-one's ever going to have been able to see that
0:56:21 > 0:56:23all the way through.
0:56:23 > 0:56:27- Doesn't it look fantastic? - I know, it's mad!
0:56:28 > 0:56:30I can't believe it's finally done.
0:56:32 > 0:56:34Feels so good.
0:56:34 > 0:56:39Like, we're directly below the docks right now and you wouldn't know.
0:56:39 > 0:56:43I know. Hello, metres of water there above us.
0:56:43 > 0:56:47Oh, my gosh, we were working like dogs, weren't we, 24/7?
0:56:47 > 0:56:49It couldn't have been closer. It couldn't have been closer.
0:56:49 > 0:56:51We've done it.
0:56:55 > 0:56:56A couple of years ago
0:56:56 > 0:56:59when I was standing in a steel-lined structure I had no idea, I couldn't
0:56:59 > 0:57:02even envisage what it would be like when we were finished.
0:57:02 > 0:57:04It just seemed like we had so much work ahead of us.
0:57:04 > 0:57:06It was never ever, ever going to end.
0:57:10 > 0:57:13For me to have it as my first job is amazing.
0:57:13 > 0:57:16I think I'm going to disappointed at everything else I go to now.
0:57:23 > 0:57:27This is the new Connaught Tunnel for the next 120 years.
0:57:29 > 0:57:31You need to get out of the way here
0:57:31 > 0:57:33because trains are going to start coming through!
0:57:36 > 0:57:41The new £15-billion railway is due to be open to the public by 2018.
0:57:44 > 0:57:47There's a huge amount of work still to do before a single train can run.
0:57:49 > 0:57:53Workers must gouge out space beneath the city's crowded streets
0:57:53 > 0:57:55for ten enormous new stations.
0:57:55 > 0:57:59It's hard to imagine that in another five years this will be teeming
0:57:59 > 0:58:02with passengers, there'll be swanky new trains coming through
0:58:02 > 0:58:05and it will all be an architectural masterpiece.
0:58:07 > 0:58:09Building these structures will not only be
0:58:09 > 0:58:11a big engineering challenge...
0:58:11 > 0:58:15Beautiful! Beautiful! Looking more than good, looking brilliant.
0:58:16 > 0:58:20But it will also reveal lost secrets of London's past.
0:58:20 > 0:58:23It's exciting, this is one of the first times within this
0:58:23 > 0:58:26immediate area that we've actually found several skeletons together.