Shanghai will be extending its maglev train line to the Hongqiao Airport, as part of a high-speed transport link between Shanghai and Hongqiao.
Shanghai will be extending its maglev train line to the Hongqiao Airport, as part of a high-speed transport link between Shanghai and Hongqiao.
Maglev Trains: On Track with Superconductivity
If you’ve finished reading our primer on superconductivity, you may well be asking yourself, “OK, the science is very cool. But what’s this all mean for me?”
Well, for one, it could mean that you’ll be zipping across town or across country one day at hundreds of miles an hour on a train that flies through the air.
Around the world, scientists and engineers have been developing maglev trains – trains that levitate above a magnetic field. Although there are systems (such as Germany’s Transrapid system) that use electromagnets rather than superconducting magnets, we’ll limit our explanation here to the type of train that harnesses superconductor technology. Such electrodynamic (suspension) systems (EDS) are currently in experimental use or under development in Japan and Florida.
Many believe this mode of transportation holds great promise and offers considerable advantages. The train cars are less expensive to build than traditional railway cars and are relatively quiet. The tracks take up less land. These trains use far less energy than other types of transportation and don’t pollute. And they put today’s “express” trains to shame, rocketing by at an average 250 mph that can climb much higher. Proponents say an underground maglev could one day shuttle you from the Atlantic to the Pacific in just one hour!
The beauty of maglevs is that they travel on air. The consequent elimination of friction means much greater efficiency. Just as electrons move more efficiently through a superconducting wire because there is no resistance, so, too, does a maglev travel more efficiently than a regular train because there is no friction between the wheels and the track, thanks to the Meissner Effect.
The train itself is equipped with several superconductors, while a series of electromagnetic coils run along the length of the track. When the train approaches these coils, the superconductors induce a current in them that works to both levitate the train several centimeters above the track and to center it between the guide rails.
That’s achieved by a second series of electromagnetic coils, which run alongside the levitation/guidance coils. After the train reaches a certain speed, these propulsion coils kick into gear. They receive a constantly alternating electric current that changes the polarity of the coils in such a way that they are always arranged to push or to pull the onboard superconducting magnets of the passing train. In essence it’s a motor – not a circular one, like the one in your car, but linear, running the length of the entire track. The beauty, though, is that only the coils that are in the vicinity of the moving train at any point in time need be engaged.
 Shanghai's maglev train started commercial service in 2003 |
The state-run publication said the price could increase to 500m yuan ($69m; £35m) per kilometre of the 31.8km extension, up from 200m yuan.
It puts the increase down to a revised route to avoid densely populated areas.
Maglev trains use electric-powered magnets to float above their tracks, allowing for super-fast speeds.
The newspaper report said the cost increase had also been caused by plans to increase the buffer zone around the track, to take into account residents' concerns about exposure to electromagnetic radiation and noise.
Floating train
Shanghai currently has the world's only commercial maglev service, where the floating train has whisked travellers between the city's main airport and the financial district since 2003.
The planned extension will connect with the city's second airport.
The Chinese government and a German consortium including Siemens, which helped develop maglev technology, have also discussed the possibility of extending the line by 160km to the city of Hangzhou.
Last year, Germany said it had come up with the funds to launch its own maglev rail service.
The state of Bavaria is to build the high-speed railway line from Munich city centre to its airport.
Japan is also now actively exploring the introduction of maglev services.
The world's first commercially operating maglev railway was at Birmingham International Airport in the UK.
From 1984 to 1995, it shuttled passengers 600m from the main terminal to the nearby railway station.
But after 11 years in operation, it was hit by reliability problems and replaced by a conventional system.
Although maglev allows for speeds substantially higher than traditional railway lines, critics point to its much higher costs of installation.
 Munich is following in Shanghai's footsteps |
| HOW MAGLEV TRAINS WORK  Opposite poles on magnets keep train above track Train is propelled by electro-magnetic system in the sides of the "guideway" instead of onboard engine Top speed (with passengers) - 450km/h (280mph) Developed by Transrapid Int in Germany Operating commercially in Shanghai Test facility in Emsland, northern Germany, is longest of its kind at 31.5km (19.5 miles) Source: Transrapid International Deadly crash on German monorail
The train, which floats on a monorail via a magnetic levitation system called maglev, was going at nearly 200km/h (120 mph) when it crashed near Lathen. Damaged carriages were left balancing on track 5m (16ft) in the air, hampering rescue efforts. "Today we are in mourning," said Chancellor Angela Merkel at the scene. The accident happened at about 1000 (0800 GMT), on a 31.8km (20 miles) test track from Lathen to Doerpenwhich is used for tourist trips and to demonstrate the technology. |
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