01-06-2012, 12:20 PM
MagLev: The Train of the Future
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TOMORROW’S TRAIN
Trains have affected our daily lives ever since they were first conceived and built. Trains have been helping us move large amounts of cargo or people at one time. The earliest trains consisted of only wooden tracks and horse drawn wagons. It was easier to move cargo over these wooden tracks than on dirt roads. This was the beginning of modern railroads. By 1776, iron had replaced the wooden wheels and tracks [1]. The invention of steam engines helped fuel the industrial revolution and helped move tons of supplies over a long distance.
Steam engines were better than other modes of transportation during the mid-1800’s. They were fast, comfortable, and could carry many people at one time. Steam engines have evolved since then. Even though they have evolved, they are slow. Diesel trains and electrical trains could carry people/cargo much faster than steam engines could. Yet in this ever growing world of ours, we need a faster mode of land transportation.
HISTORY AND DEVELOPMENT
Maglev has been a long standing dream of railway engineers for the past century. These engineers envisioned a train that could float above its tracks. They saw the enormous potential for a train like this. The vision of Maglev began in the beginning of the 20th century with two scientists.
Early Dreams
In 1904, Robert Goddard, who was a college freshman at the time, wrote a paper proposing a form of frictionless travel by raising train cars off the rails by using electromagnetic repulsion roadbeds [2]. He said the train would travel at super fast speeds. In 1910, Emile Bachelet applied for a patent on a rail car which for levitation would use alternating-current electromagnets and for propulsion would use solenoids at intervals along a road-bed [2]. Bachelet’s dreams couldn’t be realized because his concept used too much power for conventional magnets [3].
In the early 1920s, a German scientist named Hermann Kemper pioneered in work in attractive-mode Maglev [4]. He received a patent for magnetically levitating trains. Kemper continued to research and pursue his concept through the 1930s and 1940s and established the basic design for practical, attractive-mode Maglev in a 1953 paper [4].
German Development
In 1969, the German government sponsored a research project which built their first full scale model of a Maglev design [6]. They called their version of the Maglev the TransrRapid 01. A few years later, the first passenger Maglev debuted and carried people for a few thousand feet at speeds of only 50 mph. The German company, Munich’s KraussMaffei, which built the first TransRapid, continue to build improved versions of the TransRapid in a joint private-public funded research effort. In 1971, they completed the TransRapid 02. They completed the TR 03, TR 04 in 1972 and 1973, respectively. The TR 04 set a new speed record for passenger MagLevs by going 157 mph in December of 1973 [6].
Germany’s first large scale demonstration of the TR was in 1979 was at the International Transportation Fair in Hamburg, where the TR 05 carried about fifty thousand visitors between a parking lot and the exhibition hall for six months [6].
Lateral Guidance System
The Lateral guidance systems control the train’s ability to actually stay on the track. It stabilized the movement of the train from moving left and right of the train track by using the system of electromagnets found in the undercarriage of the MagLev train. The placement of the electromagnets in conjunction with a computer control system ensures that the train does not deviate more than 10mm from the actual train tracks [8].
The lateral guidance system used in the Japanese electrodynamic suspension system is able to use one “set of four superconducting magnets”[8] to control lateral guidance from the magnetic propulsion of the null flux coils located on the guideways of the track as shown in Fig. 1. Coils are used frequently in the design of MagLev trains because the magnetic fields created are perpendicular to the electric current, thus making the magnetic fields stronger. The Japanese Lateral Guidance system also uses a semi-active suspension system. This system dampens the effect of the side to side vibrations of the train car and allows for more comfortable train rides [9]. This stable lateral motion caused from the magnetic propulsion is a joint operation from the acceleration sensor, control devive, to the actual air spring that dampens the lateral motion of the train car.