Fehmarn Belt will be Longest Tunnel in the World

Slated at $10 billion, construction on the Fehmarn Belt Fixed Link could start as early as this year. At 11 miles long, the completed project will be the longest immersed tunnel in the world. It will run beneath the Baltic Sea and connect Denmark to Germany between the islands of Lolland and Fehmarn. Long in the planning, the bill finally giving the project the green light passed its first reading in the Danish Parliament this month. Construction could be completed as early as 2024.

The completed tunnel would help to connect Denmark and Southern Sweden to Europe’s heartland by slashing the detours currently necessary to travel through the Danish archipelago. Currently, to reach Hamburg from Copenhagen/Malmö by train a 100-mile detour to the west via Jutland must be taken. By road, a 45-minute ferry must be included. To reach Berlin by road takes roughly 6 hours.

The new tunnel would decrease the travel time by rail from Copenhagen to Hamburg from about 5 hours to about 2 hours. Accomplished with a mere 7 minute crossing under the Fehmarn Belt.

The tunnel will be composed of 710-foot-long sections that will be subdivided into two rail tunnels, two three-lane one-way highways and a service tunnel running between them. These sections will be sealed and floated out to a trench, where ballast tanks placed on them will be filled with water, forcing them down in the cavity. The tranches will then be filled with gravel and topped with stone.

The price tag on the project has not been a problem with the Danish; however, German resistance is a little stronger. Beyond its financial contribution to the tunnel the Germans will have to overhaul railways to connect to the tunnel. There does exist an alternative scheme for crossing the Western Baltic – a bridge or tunnel that would link the Danish island of Falster with the city of Rostock. This seems unlikely, though, as the Fehmarn Belt is projected to be the most cost effective.