Over the past half-century, a lot of tunnel concepts that were seen as theoretical became possible thanks to improved infrastructure, advanced technology and developments in safety that made them viable in the long term.

 

Probably the most famous example of this in the UK is the Channel Tunnel, with similarly revolutionary tunnels found in Europe with the Gotthard Base Tunnel and the upcoming Rogaland Fixed Link.

 

Whilst practically all tunnels are designed to cut journey times, the former two, in particular, have become vital arteries of the transportation network, with fortune favouring the bravery to invest in infrastructure on that scale.

 

However, there has been one tunnel project that has been on the minds of futurists for over a century but has not only been seen as unfeasible and economically irresponsible but also literally impossible.

 

Ignoring that the estimated price of such a tunnel would be close to £15tn, is it necessarily impossible for such a tunnel to be made?

 

An Express Of The Future

The first reference to a transatlantic tunnel might be found in the short story An Express of the Future, written by Jules Verne’s son Michel.

 

It has been a common topic in science fiction, with The Tunnel being a very popular novel and film in the 1930s, whilst 2001: A Space Odyssey author Arthur C. Clarke mentioned the concept in the novel The City and The Stars.

 

It is a concept that captures the imagination because the idea of a physical link between Europe and the United States given their distance from each other retains a lot of appeal.

 

There is also a sense that it can’t be literally impossible, given that transatlantic cables have been laid on a regular basis and other tunnel projects that were considered just as impossible in the past have been opened.

 

However, the Atlantic Ocean is one of the hardest places to construct anything, let alone a tunnel which crosses it from one continent to the next.

The Atlantic Ocean is extremely deep, filled with strange currents and ocean movements that have historically snapped undersea cables and could potentially devastate a tunnel that would, for reasons that will be explained, need to be completely watertight.

This has made the option of floating the tunnel just 50m underwater, secured by tethers, rather suspect, especially given the risk of icebergs and underwater vessels.

Alternate plans involve laying the tunnel at the bottom of the ocean, underneath the ocean floor entirely, or a combination of both methods as and where they are feasible.

That has not stopped serious considerations from being made despite these difficulties, in no small part because the potential benefits are so vast.

An undersea tunnel would likely be significantly faster than travelling by sea using a conventional train, but it would also potentially open the door for much faster forms of transport.

Specifically, two types of ultrafast trains could be potentially used, and both have been proposed by different theoretical plans for the tunnel.

One of these is a jet train, which would use hugely powerful rockets to force train carriages ahead at speeds far exceeding high-speed rail, potentially reaching thousands of miles per hour depending on the type of engine used.

The only problem with this, outside of the enormous fuel cost, is that it would take 18 minutes to reach this top speed and 18 minutes to slow down in order to not enter Euston or Penn station at a speed so fast it would rip a hole in one of the world’s biggest cities.

This would not exactly be comfortable and would make the ear-popping feeling associated with long-distance flying feel positively comfortable by comparison. One proposal to fix this would be automatically rotating seats that would make the tilting feeling feel more akin to a comfortable recline.

The other option would be a vacuum train, a currently hypothetical form of magnetic levitation train that travels through a partial vacuum. The theory is that with less air resistance, such trains could potentially reach speeds as mind-bogglingly fast as 5,000mph.

This would appear to be the most plausible option and has led to claims that such a tunnel, were it created, would allow people to travel from London to New York in less than an hour.

That headline claim is likely the reason why such a plan has not been entirely dismissed, even if it would take longer than the Sagrada Familia to construct and cost more than the GDP of every country in the world outside of China and the United States.