Maglev trains trains of the future Authors: Tomasz Pośpiech Mateusz Grzesik
Plan of presentation What is Maglev? How does Maglev work? Advantages of Maglev Trains Description of existing and planned lines of Maglev system Summary: pros and cons Sources
Maglev is a type of the unconvetional rail system which uses an electromagnetic force as suspension instead of traditional wheels, axles and bearings. Force is created by strong electromagnets in such Maglev systems as German Transrapid. The second type of Maglev trains uses for suspension superconducting magnets and physics phenomena called Meisnner s Effect (i.e Japanese SCMaglev). Maglev trains just levitate few centimeters above steel rail, so there is no friction and less energy is consumed for movement. Maglev trains can easily speed up to 600 km/h in oper air. But the most fascinating facility of Maglev is an ability to speed up even to orbital speed (approx. 28800 km/h) if we run train in a vacuum tunnel. Consumed energy is less than in traditional railway, even if we are close to the orbital speed, so this is definitely the way that future transport will aim. What is Maglev?
How does Maglev work? German Maglev system called Transrapid uses strong electromagnets which force train to levitate. One magnet on each side of vehicle pull up train to the safe distance above rail (about 10 mm) and second magnet affects with steel guidance rail assembled into track to prevent falling train from construction. Transrapid gains speed owing to linear motor system installed in track. By propulsion (changing direction of magnetic field) there is created a horizontal magnetic force which speeds up vehicle. LMS is used for braking as well.
How does Maglev work? Japanese version of Maglev system uses superconductors to prepare magnetic bag. Train sits on bag and levitate about 10 cm above the rail. Superconductor is a special material which electrical resistance in certain conditions decreases to zero. If we put superconductor into magnetic field, the physical phenomena called Meissner s Effect will be activated. Object which has no electrical resistance will be pushed out from that magnetic field and start to levitate. Scientists have already discovered superconductors that work in temperatures that occur in our natural environment but they are very unstable, at present. To provide stability and safety, constructors have to use stable superconductors which have to be cooled down to temperature below -170 C to reach electrical resistance equal zero. Hence in Japanese version of Maglev train there are containers with liquid nitrogen assembled to vehicle which cool down superconductors.
Advantages: velocity Maglev trains in oper air can reach speed over 400 km/h much easier than traditional high-speed railways because there is no friction between wheel and steel rail. Maglev trains in vacuum tunnel can speed up to amazing 8 km/s because there is no friction as well as environment resistance. There is already developed technology which makes Maglev able to unhook selected part of train in full-speed mode. There is no need to stop whole train, i.e on station. We can just detach one wagon and guide it into station while the rest of the vehicle will remain in fullspeed motion. After passengers change that wagon is dispersed to full speed and attached to the next train on line. In 2003, Japanese version of Maglev train reached a maximum speed of 581 km/h and beated TGV in world speed record for rail vehicles.
Advantages: safety Maglev train can only run in one direction on each track because of propulsion, so there is no chance to front collision. There is also no risk for rear collision because if two trains on track will be close enough to each other, they will repel themselves like two magnets with the same pole. In Japanese Maglev the stronger train presses onto magnetic bag, the stronger magnetic forces pull train up, so there is no risk for going off the rail. In German Transrapid, computer system precisely adjust gaps between train and rail, but even if the system fails, vehicle will just sit on rail and stay safe. Lateral forces are nivelated by support electromagnets (Transrapid) or by guidance coils assembled to track (Maglev). Train cannot be knocked out by wind etc.
Advantages: economy Maglev trains are much more energy efficient than traditional railway, because there is no friction between wheel and rail. The only resistance that train have to handle with is the air resistance, which is significant and economically non-profitable for speed over 600 km/h. In vacuum tunnel, there is no air resistance, so train won t have any energy loses from motion. About 90% of energy used for granting speed can be recovered during the braking process. Transportation using vacuum train can be incredibly cheap, hence Maglev train could transport even such common goods as water or sand. Infrastructure for Maglev can be hid underground or elevated above city infrastructure so there is no much space occupation. Maglev line can be built from prefabricated concrete blocks which is fast and easy. There are also much lower costs of maintenance than in traditional railways. System is silent and eco-friendly as well.
Description of existing and planned Maglev railroads China: The railroad was constructed in 2004; 30 km (red colour) The average speed is 430 km/h Until 2009 the amount of people who was transported on line was 23 mln Railroad in planning: 200 km (orange colour)
USA: Las Vegas-Primm: the length of the railroad 56 km Pittsburgh International Airport-Greensburg: the length of the railroad 87 km Baltimore-Washington: the length of the railroad 63 km Atlanta-Hartsfield International Airport : the length of the railroad 50 km The average speed on the tracks is 400 km/h
United Arab Emirates : Great Britain:
Summary: pros and cons Pros: High level of safety (there is practically no chance for the train to get derailed or to collide with an another train) Cons: Highly expensive investment (1 km costs average 16 mln USD but can be up to even 50 mln USD if we want build vacuum tunnels) Short travel time (caused by vey fast speed, over 400 km/h) Low operation cost caused by no friction force between the vehicle and the rails and low power supply cost Maglev in vacuum tunnel is perfect candidate for revolutionizing the word transportation system Silent and ecologic transportation system
Sources www.grzesik.wordpress.com www.transrapid.de www.swissmetro.ch www.maglev2000.com www.wikipedia.org Thank you for your attention.