Name: How Engineers Soundproof a New Underground Train Track
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Construction teams use springs to quiet the Elizabeth Line trains as they pass under a concert hall.

Part of the new London track is directly below an iconic performing arts center.

How Engineers Soundproof a New Underground Train Track

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Construction teams use springs to quiet the Elizabeth Line trains as they pass under a concert hall.

Part of the new London track is directly below an iconic performing arts center.

Tech & Engineering

How Engineers Soundproof a New Underground Train Track Published January 31, 2023Narrator: Once the trains start running, these tunnels will be noisy. But right here, the project faces one of its most difficult construction challenges. The team needs to reduce the amount of noise coming from this section of track.Gregg Purcell: Here we are directly beneath the Barbican, right directly beneath.Narrator: Opened in 1982. The Barbican Center is an international hub for arts and culture. London's equivalent of Carnegie Hall. The center's largest venue, Barbican Hall, sits one story below ground.Huw Humphreys: Barbican Center is, the home of the London Symphony Orchestra, presents regular seasons from the Royal Shakespeare Company. It really is one of the truly great artistic centers 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.Narrator: And that's the problem. Barbican Hall sits just 55 feet 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 are using ingenious floating tracks, unique concrete slabs of rail track that sit on special springs. As a train passes over these springs, they should absorb most of the energy and reduce noise reaching the theater.Gregg Purcell: Floating tracks that allows that noise to be brought down even lower on the surface. You won't hear anything when you're watching Hamlet.Narrator: It takes over 150 tons of concrete reinforced with steel bars to form each hundred foot long floating track slab.Gregg Purcell: We've got all the reinforcements complete. These spring houses are all installed. We've got all the rail. And this slab has been set up to pass the concrete on top. That's the liquid gold coming out there.Narrator: Once set, they screw the springs into place on the underside of the slab and raising to its final height. With the slabs now cushioned by the springs, they can set the rails on top. With this crucial section of the railway in place, the team can pick up the pace and lay track throughout the rest of the tunnels.

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How Engineers Soundproof a New Underground Train Track

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