Transatlantic tunnel

A transatlantic tunnel is a theoretical tunnel which would span the Atlantic Ocean between North America and Europe and would carry mass transit of some type—trains are envisioned in most proposals. Using advanced technologies, speeds of 500 to 8,000 kilometres per hour (310 to 5,000 mph) are envisaged.

Plans for such a tunnel have not progressed beyond the conceptual stage, and no one is actively pursuing such a project. Most conceptions of the tunnel have it between the United States and the United Kingdom, or more specifically, New York City and London. The main barriers to constructing such a tunnel are cost—from $175 billion to $12 trillion—and the limits of current materials science.

Existing major tunnels, such as the Channel Tunnel and Seikan Tunnel, despite using less expensive technology than proposed for the transatlantic tunnel, struggle financially.

A transatlantic tunnel would be 88 times longer than the Gotthard Base Tunnel and 36 times longer than the Delaware Aqueduct. In 2003, the Discovery Channel's show Extreme Engineering aired a program entitled "Transatlantic Tunnel" which discusses the proposed tunnel concept in detail.

History

Suggestions for such a structure go back to Michel Verne, son of Jules Verne, who wrote about it in 1888 in a story Un Express de l'avenir (An Express of the Future). This story was published in English in Strand Magazine in 1895, where it was incorrectly attributed to Jules Verne, a mistake frequently repeated today. In 1913, the novel Der Tunnel was published by German author Bernhard Kellermann, which inspired four films of the same name: one in 1914 by William Wauer, and separate German, French, and English versions released in 1933 and 1935. The German and French versions were by Curtis Bernhardt and the English was written in part by science fiction writer Curt Siodmak. Suggesting contemporary interest, an original poster for the English version was estimated at auction for $2,000–3,000.

Robert H. Goddard, the father of rocketry, was issued two of his 214 patents for the idea. Arthur C. Clarke mentions intercontinental tunnels in his 1956 novel, The City and the Stars. The 1975 novel, A Transatlantic Tunnel, Hurrah!, describes a vacuum/maglev system on the ocean floor. The April 2004 issue of Popular Science suggests a transatlantic tunnel is more feasible than previously thought and without major engineering challenges. It compares it favorably with laying transatlantic pipes and cables, but with a cost of 88 to 175 billion dollars.

Variations

Many variations of the concept exist, including a tube above the seabed, a tunnel beneath the ocean floor, or some combination.

A 1960s proposal has a 3,100 miles (5,000 km) long near-vacuum tube with vactrains, a theoretical type of maglev train, that could travel at speeds up to 5,000 miles per hour (8,000 km/h). At this speed, the travel time between New York City and London would be less than one hour. Another modern variation intended to reduce cost is a submerged floating tunnel about 160 feet (49 m) below the ocean surface to avoid ships, bad weather, and high pressure (associated with a tunnel deeper at the sea bed). It would consist of 54,000 prefabricated sections held in place by 100,000 tethering cables. Each section would consist of a layer of foam sandwiched between steel. It too would have reduced air pressure. The cables would be anchored into the seafloor, and would have room to sway if a submerged object like a submarine were to hit the tunnel. If a breach were to occur in the tunnel, the trains would be going faster than the water and would be blocked off from the breached section by titanium pressure lock doors, unless, of course, the breach occurred somewhere in front of the train's path. The train would not have enough time to slow down to avoid the doors and/or the breach which would cause a major crash (at up to 5,000 mph) and most likely destroy those sections of the tunnel. Theories proposing rocket, jet, scramjet, and air pressurized tunnels for train transportation have also been proposed. In the proposal described in the Extreme Engineering episode, it would take 18 minutes to reach top speed, and 18 minutes at the end to come to a halt. The resulting 0.2G would lead to an unpleasant feeling of tilting downward during the deceleration phase, and it was proposed that the seats would individually rotate to face backwards at the midpoint of the journey to make the deceleration more pleasant. However, spinning chairs would also cut down massively on passenger capacity, and would also be expensive, therefore raising the cost per ticket to a much higher level.

A proposed alternative route suggests an approximately 6000 km route mixing sea and surface, travelling north from Newfoundland over the ice sheet of Greenland and across Iceland to the Faroe Islands and then Scotland. This route would be cheaper to build because it could have multiple tunnel heads, but more difficult to construct, due to adverse weather conditions in Greenland and the difficulty of maintaining the system near the ice sheet. Lessons learned from the Trans-Alaska Pipeline System might mitigate such difficulties. Building a railway over an ice sheet has never been considered. Roads built on ice sheet do exist in a few places (Svalbard and Antarctica), but there are problems at the edge of the sheet and due to ice streams. Unlike a roadway, a high-speed railway must be stable.