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First Segment of the Fehmarnbelt Tunnel Is In Place (heise.de) 102

Longtime Slashdot reader Qbertino writes: The Fehrmarnbelt tunnel is a European construction megaproject building a tunnel between Denmark and Germany, crossing the Fehmarnbelt in the Baltic sea. The first segment of the tunnel has now successfully been placed in its designated spot. This is a yet-unseen, next-level engineering feat achieved by the Danish Sund & Baelt construction company. It took 14 hours and used a massive pontoon ship built specifically for this project.

The tunnel segments are 217 meters long, weigh more than 73,000 metric tons, and have to be placed within a tolerance of 3 mm. The tunnel will eventually consist of 89 of these segments, be 18 km long, and connect the Danish city of Rodby with the German island Fehmarn through five individual tunnel tubes: two for cars, two for trains, and one rescue and maintenance tunnel. Crossing time will be reduced from a 45-minute ferry crossing to seven minutes by train or 10 minutes by car, and cut the travel time between the German city of Hamburg and the Danish capital, Copenhagen, down to 2.5 hours. The project's planned completion is set for the year 2029. German news Tagesschau has some details and a neat animation, while further details are available from the German tech news site Heise.

First Segment of the Fehmarnbelt Tunnel Is In Place

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  • I liked that ferry (Score:5, Interesting)

    by Misagon ( 1135 ) on Friday May 08, 2026 @07:58AM (#66133762)

    I have travelled the ferry between Roedby and Puttgarden several times on a train.
    It had felt a little unsafe to get out of the train to leave your belongings behind during the crossing, but it was a nice change of pace.
    It was nice to get out on the deck and get a view of the Femern Baelt straight. That is something that future train travellers will be denied.

    The worst part was for the train sometimes having to wait for the next ferry. That time should also be accounted for when calculating time savings.

  • More information (Score:4, Informative)

    by necro81 ( 917438 ) on Friday May 08, 2026 @08:03AM (#66133768) Journal
    Practical Engineering has a video [youtube.com] about this project on Youtube, as does the B1M channel [youtube.com].

    Having taken the train from Copenhagen to Hamburg before, this will be a massive improvement.
  • by evanh ( 627108 ) on Friday May 08, 2026 @08:19AM (#66133778)

    A news article posted on Slashdot that hasn't been stripped of the original metric numbers! Refreshing.

  • "The tunnel segments are 217 meters long, weigh more than 73,000 metric tons, and have to be placed within a tolerance of 3 mm."

    I simply can't imagine why it wouldn't be orders of magnitude cheaper and faster to just use short segments that don't need to be aligned so precisely.

    I used to think that maybe I, a simple country ignoramus, just wasn't equipped to understand the Wonders of the Modern Age. But the more glimpses I snatch of the wiring and plumbing of the Wonders, the more I think somebody in admin

    • by Anonymous Coward
      That's probably why they're building the tunnel and not you.
    • by ceoyoyo ( 59147 )

      Hey, can you imagine how much better the plumbing in your house would be if the pipes were a bunch of 1 inch sections connected by joints?

      I don't know why you'd think the short sections would have to be aligned less precisely. A 1 mm error multiplied by a a couple thousand joints between 10 m sections has a good chance of being a lot bigger than a 1 mm error multiplied by 80 joints.

      I used to think that maybe I, a simple country ignoramus, just wasn't equipped to understand the Wonders of the Modern Age.

      Nons

    • I simply can't imagine why it wouldn't be orders of magnitude cheaper and faster to just use short segments that don't need to be aligned so precisely.

      So having 100 times the number of segments but now all with poorly aligned joints would be better?

      I used to think that maybe I, a simple country ignoramus, just wasn't equipped to understand the Wonders of the Modern Age. ...

  • by PPH ( 736903 ) on Friday May 08, 2026 @10:37AM (#66134006)

    From TFA:

    The Fehmarnbelt link is funded by loans and will be paid for by its users.

    So much for the Nordic Model [wikipedia.org]. I would grieve the death of Socialism over Karl Marx's grave. But there's a fee to get in to see it.

    • The "loans" are 100% state funded loans by the Danish government who is footing 100% of the bill. The idea of tolls was largely due to the realisation that non-Danish people will be some of the biggest beneficiaries and that socialism only works if costs are distributed among the society itself, and not just half of it.

      • by PPH ( 736903 )

        socialism only works if costs are distributed among the society itself, and not just half of it.

        Please come to Washington State and tell our legislature this.

  • Imagine, 73k tonnes dropped with 3mm accuracy. That's frikkin impressive!
  • The tunnel segments... weigh more than 73,000 metric tons, and have to be placed within a tolerance of 3 mm.

    That is mind-blowing.

  • by hackertourist ( 2202674 ) on Friday May 08, 2026 @11:19AM (#66134080)

    That's not a series of tubes, THIS is a series of tubes!

  • The video describes how the tunnel segments float and how they fill sections with water to ballast and position the segments. I understand that perfectly. Clever.

    But, then the water is pumped out to make the tunnel usable. How do they keep it submerged? What prevents the entire tunnel popping up to the surface?

    • by ceoyoyo ( 59147 )

      They pile rocks on top.

    • But, then the water is pumped out to make the tunnel usable. How do they keep it submerged? What prevents the entire tunnel popping up to the surface?

      4700 metric tons of balast, rocks and gravel per segement. Sorry, didn't mention that in the GP post but it's in the articles and videos.

  • I guess it's not an autobahn.

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