Digging Massive Tunnels Deep Under London

Workers are tunneling out a whole new Underground

London's Crossrail is a railway system -- currently the largest construction project in Europe -- that will run partially underground, and is designed to create a faster link between the center of London and its outlying areas. Trains will start running in 2018. Since construction started in 2009, 23 miles of tunnels have been burrowed under the streets of London. Crossrail Limited, the company that is running the project, just released new photos of the huge tunnels.

When the 26 miles of tunnels that make up Crossrail are complete, and the trains are running, the new network will cut travel times dramatically, and serve an estimated 200 million people. The excavated material from the tunnels will be used to create a 1,500 acre nature preserve.

Check out more photos of the Crossrail tunnels here or, closer to home, revisit the progress of New York's long-anticipated Second Avenue Subway.

Tunneling Machine

Tunneling Machine

Workers stand in front of the nearly 500-foot-long tunneling machine named ElizabethCrossrail
Crossrail Platform Tunnels

Crossrail Platform Tunnels

Crossrail
Farringdon Platform Tunnel

Farringdon Platform Tunnel

Robby WhitfieldCrossrail