First tunnel element of the Fehmarnbelt Tunnel immersed
26 points
3 days ago
| 3 comments
| arup.com
| HN
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Liftyee
58 minutes ago
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I'm amazed that engineers can make submerged tunnels work and that leaks don't (literally) sink the whole plan.
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ianburrell
6 minutes ago
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The Transbay Tube carrying BART across the bay is immersed tube. The sections were welded together by divers. The sections were filled with water and then pumped out.

Fehmarnbelt tunnel sections are concrete. I couldn't find how they are connected by concrete would make sense.

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yrcyrc
34 minutes ago
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Very nice video explainer https://public.skyfish.com/p/sundogbaelt/2675422/70675433?pr...
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readthenotes1
42 minutes ago
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52.6B krone for 18 km

8B USD for 11 miles

CACHSR IOS 36B USD for 171 miles.

The Merced to Bakersfield IOS looks like a bargain on a distance basis. I have no idea of the carbon offset or passenger time saving versus flying of course

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Melkman
12 minutes ago
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They are not really comparable are they. One is a rail connection over land and the other is a 130ft deep tunnel for rail and road traffic.
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bradchris
32 minutes ago
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Well, if we’re comparing CA infra costs, for a more 1-1 comparison you can look at the $9.7B Los Angeles is spending on building out a long-awaited subway line (phase 1 of 3 opened Friday!) and see how tunneling underwater looks like a bargain in comparison.

https://www.latimes.com/california/story/2026-05-07/los-ange...

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