Alex Nazzari Ms. Sicola SUPA English Period 8 21 January 2015 The History and Development of Maglev Trains Worldwide

Transcription

1 Nazzari 1 Alex Nazzari Ms. Sicola SUPA English Period 8 21 January 2015 The History and Development of Maglev Trains Worldwide A Maglev is an abbreviated term for a magnetically levitating train. This innovative technology has produced a transportation system with many unique benefits. Over the last century, the concept of a frictionless train was created and since developed by a number of scientists. Today, two major systems of Maglev trains exist, including electromagnetic suspension and electrodynamic suspension. Germany and Japan are the two countries that are leading these competing technologies. Despite the expense of building the Maglev systems, the high speed and low energy consumption of these train present huge advantages. Friction is a ubiquitous force that resists movement; however, the technology of the Maglev train is an engineering feat that has greatly eliminated the frictional force upon the transportation system. Robert Goddard was an American rocket scientist who first envisioned a frictionless train based on a magnetic levitation in Although his ideas were respected, they were also seen as an expensive futuristic model. This is a picture of Robert Goddard with one of his first Maglev train models. Yet, by 1912, Emile Bachelet, a French engineer, had patented and built a model of a train propelled by electromagnetic levitation (Heath). In 1930, the study of magnetic field in conjunction with transportation systems grew when Hermann Kemper, a German scientist, was researching airplanes and trains. He focused on the linear synchronous motor that all subsequent

2 Nazzari 2 Maglevs use to operate. It uses guideway coils and inverters to deliver the voltage needed to create the electromagnetic forces. Then in 1969, American scientists, James R. Powell and Gordan T. Danby patented their Maglev train. Their goal was to reduce excessive traffic in New York City. Following this, the Germans and Japanese began development of their respectively Maglev trains through the 1970s. The U.S. continued to develop Maglevs and began the National Maglev Initiative (NMI) in Germany completed a line from Hamburg to Berlin in 1998 and Japan followed with a Tokyo-Osaka route finishing in 2005 (Presson). Throughout the development of the Maglev train, two basic systems have evolved. There is electromagnetic suspension (EMS) and electrodynamic suspension (EDS) (see the comparison below). The Construction of a Maglev car and the Guideway track as a form of a propulsion system. A Maglev that functions on EMS is constructed with arms that wrap around the track. On the sides, there are electromagnets that guide the car and maintain a safe distance from the track. Underneath the track on the car s arm, there are electromagnets placed to attract to those in the track (as seen in the diagram below). The workings of a German Maglev System.

3 Nazzari 3 This attraction levitates the car and according to the direction of the magnetic field the magnets are producing the car can be controlled to propel forward or decelerate. The German Maglevs, specifically the Transrapid, works with the EMS system (as seen in the picture below). Transrapid 2009 train being tested in Germany. Conversely, with EDS, the Maglev car and the guideway are both producing a magnetic field, allowing engineers to capitalize on the attractive and repulsive forces between the magnets. EDS has a guideway in the center of the track. Then an electrical power source charges the magnets along the track with alternating polarities. Inside the car, liquid helium and nitrogen are used to cool a coil and create superconducting magnets, as seen in the figure below (Heath). The superconducting coil is shown in relation to the helium refrigeration system and the guide rails. These superconducting magnets then repel the like polarity of magnets on the guideway and attract the following oppositely charged magnet (as seen in the figure below). Therefore, the quick change from repulsion to attraction that is repeated works together to levitate the train and propel it forwards (Presson).

4 Nazzari 4 A Maglev system based upon the Japanese model, using EDS technology. This design allows the car to reach incredible speeds, but the disadvantage is that at slow speeds the force is not great enough to lift the train, so other mechanical systems are needed to start the movement. The JR-Maglev is a Japanese built Maglev that uses electrodynamic suspension and low-temperature superconducting magnets (Rose). If the two systems were to be combined, the train would most likely have arms that wrap around the guide rail but also use electrodynamic propulsion to levitate and propel the train with attraction and repulsion forces. Maglev trains are being used in a number of countries, predominantly Japan and Germany. Full-size Maglevs in Germany have reached 280 mph, and the Japanese versions have clocked 343 mph. The levitation devices allow the trains to reach such incredible speeds. Many other countries are also using and developing similar technologies (as seen in the figure below). For example, The U.S. has electrified a railroad track for the Acela Express train, which reaches speeds of 150 mph. A graphic emphasizing the coils, levitation and propulsion system of a Maglev and the comparison between countries and the Maglev speeds.

5 Nazzari 5 The unique technology employed by engineering constructing Maglev trains has resulted in a transportation system with several advantages. Foremost, Maglevs can travel at much higher speeds, due to the absence of strong friction forces. The only minimal resistance the train experiences is air resistance. The speed in combination with the high weight loads or passenger capacity means Maglevs are highly efficient for transporting passenger and large cargo items across significant distances. The Maglev trains are comparable to airplane trips in terms of speed over certain distances. It offers passengers a comfortable trip and a smooth ride without the possibility of air turbulence like in an airplane. Furthermore, Maglevs are powered by electrical systems. This is not only low energy consuming, but it also avoids the use of petroleum and limits the pollution created by mass transit systems (National Transportation Library). The train also performs well in all weather conditions. Due to the levitation, the train does not rely on contact with the track to accelerate or break, which means rain, snow and ice are not such a great concern or danger (Presson). Overall, the speed, comfort and ecological benefits of Maglev make it an attractive transportation option. With all the positives of the Maglev trains in mind, there are also a few negative aspects. The initial expense of building these trains and track systems are a big challenge, but the benefits and low maintenance costs may serve a future incentive to adopt the Maglev as long-term transportation networks. Furthermore, there are health risks associated with the propulsion systems of trains. Exposure to electromagnetic radiation poses concern for cancer as well as damage to the nervous and reproductive system. Another possible side effect of prolonged exposure to such magnetic field includes depressed melatonin production and shifts in circadian rhythms (Gibbons). While these are serious risks, there is not consistent evidence or relevant studies that explain definitive causations. The original Japanese Maglev prototype ran on a direct

6 Nazzari 6 current electromagnetic field, which exposed the cabin to up to a dangerous 350 gauss; however, with proper shielding this can be safely reduced, using expensive heavy metals. Another concern is the surrounding area being constantly exposed to magnetic radiation and this can be combated with external magnetic fields that cancel out harmful radiation (Gibbons). Ultimately, precautions need to be carefully considered and met to ensure the public s health and safety. Since a Maglev is floating above its track and moving at high speeds, aerodynamics is a crucial component that engineers need to consider. Air resistance is the major force acting against a Maglev, so the design should be created to reduce drag. Early theories of aerodynamics suggested using a torpedo shape to direct the air back from that sharp point. Then curved vehicle bodies became more popular (Lejos). As seen in designs, such as the Japanese Maglev below, the steep slope and curve of the front end of a vehicle will streamline the air. An aerodynamic Maglev that was designed by the Central Japan Railroad Company Many designs have been tested to promote good aerodynamic qualities. Some models use straight-edged steep angles to reduce drag; whereas, others are quite rounded to streamline the airflow (as seen in the evolution of Maglev designs below). An evolution of Maglev Trains.

7 Nazzari 7 Friction is a force acting on all objects. For stationary objects, there is a static force of friction and, when moving, the frictional force opposes movement (as seen in the figure below). A free-body diagram showing the forces on an object, specifically the opposing force of friction. Friction has positive and negative effects on transportation systems, such as trains. For instance, friction allows a train to break, and it also keeps the wheel gripped and guided on the track. On the other hand, friction resists motion, so it drastically slows a train s speed. This is where a Maglev overcomes the frictional force, letting it reach much faster speeds. If friction were eliminated, our lives would change greatly. Any force placed on an object would set it into motion, and it would continue in that direction until it hit another object or experienced another applied force. Therefore, anything that was not anchored to the ground or an existing structure would be in motion until it hit a wall and changed direction. Ultimately, friction is a necessary force that allows people to keep order and continue living the life we now know. Although friction is such an important force, eliminating in the context of a Maglev train creates many advantages. The two Maglev systems, EMS and EDS, continue to be developed and modified. The current Maglev trains are promising models for the future of public transportation. In conclusion, the high speeds and low electrical energy consumption makes Maglev technology a favorable solution that with time may grow into a widely used system.

8 Nazzari 8 Works Cited Gibbons, John H. "The Effects of Electromagnetic Fields." File last modified on Sept PDF file. Heath, Cai J. "History and Development of Magnetic Levitating Trains." Ed. MSci Physics. Academia. N.p., Apr Web. 18 Jan < Trains>. Lajos, Tamás. "Basics of Vehicle Aerodynamics." PDF file. National Transportation Library. "National Maglev Initiative." about.com. N.p., n.d. Web. 18 Jan < Presson, Nick. "Magnetic Levitation: Emerging Technologies." Rogers State University. N.p., n.d. Web. 18 Jan < Rose, C. R., D. E. Peterson, and E. M. Leung. "Implementation of Cargo MagLev in the United States." N.d. PDF file.