Fehmarn Belt tunnel between Denmark and Germany

[Adlington]

International Railway Journal reports:

Trains will start running through the tunnel linking Germany and Denmark from 2029. Construction of the 18km Fehmarn Belt road and rail tunnel between the islands of Lolland in Denmark and Fehmarn in Germany has begun at Puttgarden on the German side of the structure.
The tunnel will be constructed by digging a trench along the sea floor, before large prefabricated concrete sections are floated out and lowered into place. Travel time by train from Hamburg to Copenhagen will be reduced to only 2h 30min. The current journey time between Copenhagen and Hamburg is 4h 30min.

Construction of the tunnel is expected to be completed in 2027 when it will then be fitted out with track and other lineside equipment. It will [be] electrified at 25kV 50Hz ac to match electrification on the Danish network. This will run for 2km into Germany before reaching a changeover to the German 15kV 16.7Hz ac system.

Here is a video showing the construction method.
BTW, the same technique was used for the Marmaray tunnel in Instanbul.

 

[Meerkat]

International Railway Journal reports:

Here is a video showing the construction method.
BTW, the same technique was used for the Marmaray tunnel in Instanbul.

Not rail tunnels but the Conwy and Medway road tunnels were immersed tube efforts werent they?

 

[Bletchleyite]

Not rail tunnels but the Conwy and Medway road tunnels were immersed tube efforts werent they?

Conwy certainly is. I remember as a kid sitting on top of Conwy Mountain (a bit of a grand name for a grassy knoll) and looking at the prepared segments lined up for use.

 

[Meerkat]

Conwy certainly is. I remember as a kid sitting on top of Conwy Mountain (a bit of a grand name for a grassy knoll) and looking at the prepared segments lined up for use.

I remember it being a fancy modern technique presented on Tomorrow's World!

 

[coppercapped]

International Railway Journal reports:

Here is a video showing the construction method.
BTW, the same technique was used for the Marmaray tunnel in Instanbul.

I think you will find that the BART tunnels under San Francisco Bay were also immersed tubes. See the description on Bechtel's web site: https://www.bechtel.com/projects/bay-area-rapid-transit-system-bart/

 

[JonasB]

International Railway Journal reports:

Here is a video showing the construction method.
BTW, the same technique was used for the Marmaray tunnel in Instanbul.

Also the same method used when constructing the tunnel part of the Öresund link.

 

[Ploughman]

What will be the water depth covering the tube?
There was a "Mighty Ships " Documentary on the other day, featuring a cruise liner, that sailed in this area, that needed a 9.5m depth.

 

[JonasB]

What will be the water depth covering the tube?

More or less the same as today, 35 m at the deepest part.

 

[Mag_seven]

International Railway Journal reports:

Here is a video showing the construction method.
BTW, the same technique was used for the Marmaray tunnel in Instanbul.

Thread reopened to allow update from @Killingworth.

 

[Killingworth]

There's an excellent 28 minute descriptive YouTube video about the building of this impressive project. It's largely going unnoticed, even in Germany. See The Insane Scale of Europe’s New Mega-Tunnel;