DAVID GREENE, HOST:
Elizabeth is the name of a giant tunnel-boring machine. And today Elizabeth will finish burrowing deep under London's East End. This is a small milestone for the British capital's Crossrail project. It's a new subterranean rail line that eventually will connect the city with other parts of the region. Let's go underground with reporter Christopher Werth.
CHRISTOPHER WERTH, BYLINE: Crossrail touts itself as the biggest infrastructure project in Europe. It's made up of 10 new train stations and 26 miles of tunnels below London. It employs 10,000 workers. And to get a view of it, Bill Tucker stands at the top of 140-foot staircase made of scaffolding that leads straight under the city.
BILL TUCKER: We're going to get ready to walk down and more importantly, walk back up when we're done.
WERTH: Someday you'll be able to take an escalator down here. But today we have to hoof it all the way down to the last few steps.
TUCKER: So you're now down at what we call pit bottom, which is the center of all the tunneling.
WERTH: Tucker is with the American contractor Bechtel, which oversees the project. He leads the way into a dimly lit underground world full of cement trucks and construction crews, everyone hard at work on a series of long, cathedral-like tunnels with ceilings that soar nearly 30 feet overhead. This, Tucker says, will serve as a new station once the rail line is up and running.
TUCKER: From one end to the other is about two and a half American football fields including the end zone.
WERTH: Work on the project began five years ago. It's due to open in 2018. And it's meant to help solve a pressing problem for Londoners.
UNIDENTIFIED SPEAKER: Please mind the gap between the train and the platform.
WERTH: The existing subway system known as the tube has grown very crowded. Tucker says Crossrail will increase transport capacity by 10 percent and provide a faster route from the center of town to Heathrow, the city's biggest airport far west of the city.
TUCKER: We'll have 24 trains an hour going back and forth through this station. So it's going to completely transform how we move around London.
WERTH: The total price tag for that transformation comes to roughly $25 billion. It was a tough sell given the recent cuts to public spending in Britain.
But London is a sprawling city of over 8 million people, and its population is growing fast. Michael Hebbert is a professor of town planning at University College London. He says this new train line will put the British capital within an hour's commute from towns far to the east and west of the city, where all those new people might live.
MICHAEL HEBBERT: What it does is it enables the city to grow without physical growth.
WERTH: Down underground, Bill Tucker is eager to connect this station with the rest of the new tunnels.
TUCKER: The first tunnel-boring machine will actually enter into this hall scheduled on my birthday, the 23 of December.
WERTH: Tucker says the tunneling machines move underground at about 100 yards per week. And with the help of technology, they arrive within a fraction of an inch of their destination.
TUCKER: In the old days, the miners used to shovels and wood. Nowadays if you watch them, it's like your children playing their video games. And we've done about eight breakthroughs so far, and every one of them has just been spot on.
WERTH: That's important, he says, because it is a tight squeeze under London. For example, right above us in the tunnels are several subway lines.
TUCKER: So at each of these stations, the planning of the route has had to be able to thread through not only the existing transportation network, but post office tunnels and sewers and water mains. And then you really don't find out exactly what's there until you start digging.
WERTH: That includes remnants from London's past, which stretches back more than 2,000 years.
JAY CARVER: Pretty much everywhere you dig in London, you're going to find evidence for the long history of the city.
WERTH: Jay Carver is Crossrail's lead archaeologist. So far he says the project has uncovered nearly 10,000 artifacts, from Roman coins to the bones of 14th-century plague victims.
CARVER: So just about every period is covered.
WERTH: He holds a Roman cremation vessel, most likely from the second century, discovered not far from where I interviewed Bill Tucker.
CARVER: What we found preserved in the pot was the burnt bones of a human cremation. This pot was also found with 30 Roman skulls, just the skulls.
WERTH: This spring Crossrail's construction will uncover a 16th-century cemetery from what used to be London's infamous Bedlam Psychiatric Hospital. Carver expects to find up to 4,000 human remains. For NPR News, I'm Christopher Werth, London. Transcript provided by NPR, Copyright NPR.