By 2030, you could be crossing the Atlantic by train

By 2030, you could be crossing the Atlantic by train
'A Day Return from Bristol to Boston, Please'
by Karl Sabbagh
Source

Amy Black is hurrying to catch her train at the Bristol terminal of Atlantic Maglev, one of the world's newest rail companies. She carries a shoulder bag containing a combined computer/ phone/credit pack and waves it at the fare detector as she passes through the barrier. The information is downloaded, her bank account
debited and her wrist screen instantly displays a seat number.

Amy settles into her seat, takes out her computer and reads over the agenda for the meeting to which she's travelling. The train doors close with a thump.
"The 10.00 GMT Davidson Flyer to Boston is about to depart," comes an announcement. "Change at Boston for onward connections to New York, Chicago, Los Angeles, Beijing, Tokyo, Vladivostok, Hong Kong, Seoul, Moscow and Berlin."

The journey time will be just over an hour and a half, with the train reaching Boston at about 6.30am local time. Since her meeting is not till eight Amy can have a full American breakfast before getting down to work.

So far, so futuristic. But this scene from the year 2030 is more than speculation: groups of engineers in the US and Japan are already looking into a global network of tubes in which trains would travel at several times the speed of sound. They believe it will replace air travel altogether.
The man behind this vision is 83-year-old American, Frank Davidson. Though a lawyer by training, he has been a major influence for 20 years in what is called "macroengineering"—thinking big about the future of engineering. He and his colleagues at the Massachusetts Institute of Technology (MIT) have dreamed up ways to transform the world of the twenty-first century, from towing icebergs to drought areas to building entire floating cities. If you think his dream of a transatlantic rail crossing is pie in the sky, consider that his last project was equally absurd—a Channel tunnel.

Always smartly dressed, Davidson does much of his work over civilized lunches. It was in a restaurant in New York in 1956 that he told a friend about a ferry trip he had taken from Boulogne to Folkestone, a crossing that took almost eight hours because of a terrible storm. It gave him an idea.

"We both remembered reading a magazine article as children", Davidson recalls, "about the attempt in the 1880s to build a railway tunnel between England and France. It was only stopped when a general expressed his worries about the tunnel being used by the French to invade Britain."

It may have taken another 35 years for the Channel Tunnel to become a reality, but the result of Davidson's efforts is now something we take for granted. The Atlantic tube too began with an article by Jules Verne in the Strand magazine in 1895, envisaging a two-and-a-half-hour subway ride from Liverpool to Boston.

But to cross the Atlantic in this time would require trains travelling more than ten times faster than even the 180 mph "bullet trains" that link Japan's major cities. There are practical limits to how fast a conventional train can go, mainly caused by friction between the train and the air around it, and between the wheels and the rails.

Davidson found that he wasn't the first to tackle the challenge of supersonic trains. American engineer Robert Goddard, who pioneered rocket technology, pondered the problem when he was still a student before the First World War. He made immaculate technical drawings—even designing seats—for a train that could go from Boston to New York in 12 minutes.

Goddard got round the friction problems by putting his train in a tube from which all the air had been pumped out. And instead of wheels he used what is called "magnetic levitation", or "maglev" for short. Many of us will remember an experiment at school where we tried—and failed—to push the north poles of two magnets together, showing that "like poles repel". If the magnets are strong enough and one is fixed to a train while the other forms the rail, a vehicle can float comfortably in mid-air on a cushion of magnetic repulsion.

Goddard himself was sidetracked by rockets, and the train designs were found only after his death in 1945. But the theory was perfectly sound. On a lecture tour to Japan, Davidson and his MIT colleagues met a Japanese engineer, already working on maglev technology, who might be able to turn Goddard's theories into reality.

Yoshihiro Kyotani is a jolly man, with a twinkle in his eye. Now 75, he has spent 40 years of his working life with Japan Railways and is one of the engineers behind the bullet train. From his office overlooking the maze of railway tracks that snakes through the centre of Tokyo he explains the technology he calls TTS—Tube Train System.
The basic principle of TTS is the same as Goddard's, although Kyotani has made one important addition—superconducting magnets. Superconductivity is the phenomenon whereby some materials, when cooled to low temperatures, lose all resistance to electrical currents. So a large circuit like a 3,000-mile maglev track could be operated with much less electricity than normal.

Ten minutes into her journey, Amy is 120 feet beneath the Atlantic, and almost 300 miles out from Land's End. She's unaware of the sea, even though it's just a few yards away. She can hear only the murmur of conversation and the occasional announcement of the journey stages. Because the maglev train is not in contact with a rail there is none of the "clackety-clack" of old-fashioned trains.

Kyotani's TTS would use magnets not only to levitate the train, but also to propel it with a series of magnetic pulses from the side of the track. Each push needn't be very large since it's the accumulation of pushes over many miles that would achieve high velocities.

The first generation of TTS trains is expected to run at 2,300 mph. In theory there is no limit to the speeds each train could reach. It just depends on how much energy you want to spend speeding them up—and slowing them down again.

For passenger services there is also the question of how much acceleration or deceleration people can comfortably bear. A reasonable compromise would be a tenth of a "g"—a force equal to a tenth of your own weight. The Atlantic tube train would probably accelerate constantly for the first six minutes of the route, cruise at full speed for an hour and ten minutes and decelerate for the final 14 minutes.

Each train could carry 1,000 passengers, the equivalent of two jumbo jets. But running costs are far less than for air travel. Passenger planes cannot begin to attain TTS speeds at normal cruising altitudes, since air resistance rises exponentially with the speed—so the faster you go, the harder it is to accelerate, leading to enormous fuel consumption and huge environmental costs.

In a vacuum, though, any increase in speed is bought at a much cheaper price, as you only have to put in energy to accelerate the mass of the train, not fight air resistance as well. And, during the constant-speed phase of the journey, little energy would be needed at all, since the train would glide under its own momentum.

These speeds are attainable because at no time will the train be in contact with anything else—even air. If it did accidentally run up against the guide rails or the tube walls at high speed, the friction would incinerate the train. TTS would therefore use computers to adjust the train's trajectory by fractions of an inch many times a second, reflecting any change in the position of the tube.

In fact, safety could be the biggest problem in selling TTS to the public, many of whom may think twice about travelling faster than a bullet several hundred feet beneath the sea. But in many ways TTS would be safer than conventional rail travel. Dedicated tubes for each direction will prevent head-on crashes and in the absence of wheels and rails, derailment would be impossible.
"And you will have no articles hitting the train from outside because it is protected by the tube," Kyotani points out. It would also be protected from bad weather.

But there are other reasons why some might not take the idea of a transatlantic tube train seriously. After all, it took seven years and £9 billion to construct 21 miles of tunnel under the Channel—how could anyone contemplate an underwater crossing more than 100 times as long? But that's the difference between a tunnel and a tube. To drill a tunnel under the Atlantic seabed would involve technology too complex and a deep-sea environment too hostile—and at the very least it would take 16 years.

A tube, however, could be manufactured in concrete sections on landthen taken by ship to where it is needed. Never more than a couple of hundred feet below the surface, the tube would be tethered either to the seabed or to floats on the surface. Across the shallower parts of the ocean, it could even be laid in a trench. Recent calculations put the cost of constructing the Atlantic tube at roughly £7 million per mile—about £20 billion in total.

The nearest you can get today to the supersonic train of the future is a hilly area near the small town of Otsuki, about an hour from Tokyo. Here, Japan Railways' 12-mile test track, which for most of its length is embedded in a tunnel, comes into the open for a mile. Every 15 or 20 minutes, with a gentle swish, a test train comes through—at more than 300 mph.

The track is part of the preparations for Japan's next generation of high-speed trains, using the maglev half of the TTS technology. But even though these trains are state-of-the-art, the fact that they run through air means they can achieve only a tenth of the speed expected for the Atlantic tube.

Other countries have plans for maglev trains. The furthest advanced is a line linking Shanghai airport to the city, but there is also a Swiss project that is even closer to TTS. Switzerland's mountainous terrain means that the conventional railway system cannot run any faster, so the proposed system would be entirely underground, using an evacuated tube. Again trains would be travelling at "only" 300 mph, but with stations every 30 to 60 miles (the whole of Switzerland is only about 200 miles from east to west), anything faster would be impractical.

Amy's train has been decelerating for nearly 12 minutes. The clock in the carriage shows both a countdown until arrival, a couple of minutes, and the local time in Boston, 6.28am. Around her, people are gathering their luggage, though some have just a briefcase or handbag: they are either day trippers like her or daily commuters. On the way out she puts her hand into the visa-detector which recognizes her handprint and allows her to go straight through immigration control.

It will probably be economic or environmental considerations that persuade industrialists and politicians to invest in a TTS infrastructure. But Kyotani sees another, subtler, benefit.

"The tube will also carry a superconducting power cable and an optical-fibre cable," he points out. "So you will be moving goods, energy, people and information quickly and freely to anywhere in the world, all in one tube. This can only foster global co-operation. When I first proposed a TTS, to go round the Sea of Japan, I was asked by the Chinese government to pass the tube through China. Then the president of Taiwan said that it should go through his country. If the world unites to develop this system, I believe it would be a major step towards world peace."

Frank Davidson has lived with this idea for a long time in the face of often sceptical reactions. "I once talked to someone very important in the aviation world and put the question to him: 'Couldn't our aeronautical people get into this?' And he said, 'Well, of course you could build it, but why would anyone wish to go that fast?'"

Davidson believes that success depends on one key step. "We're trying to get beyond mere co-operation among engineers and include lawyers, bankers, psychologists, ecologists, the whole works. Otherwise you just don't get things done. In the old days it was a little easier: the emperor of China simply decided to build a grand canal, and did."

Amy scans the departures board. Faced with a two-hour discussion of broadband media strategies for next season's advertising campaign, she suddenly flirts with the idea of playing truant. She could take the 09.00 to Los Angeles and be there by 7.30am local time or, for something more exotic, the 9.30 to Beijing via Alaska and Siberia. If she wanted to avoid jet lag (or should that be tube lag?) she could zip south to Lima in Peru.

But she thinks of her husband and son. If her meeting doesn't get bogged down she can catch the 3pm return train and be back with them in Bristol in time for a late supper.

She steps out of the terminal and her day begins for a second time.