Magnetic levitation technology has not matured to an economically viable level at this point, but its applications to a variety of fields are nonetheless quite intriguing. Its applications to transportation, in particular, have been quite evocative among futurists who look to levitation as the next big technology. Currently, maglev trains have received a lot of interest from governments and corporate interests. Shanghai already has a maglev train in operation, indicating that the technology is already viable to a certain extent. However, the track is relatively short, and it was built at great expense. Expansion of this form of transportation will require many more developments in order to reduce the cost. Magnetic levitation involves the fields of chemistry, physics, and potentially nanotechnology. In particular, magnets must be super-cooled in order to provide an efficient mode of levitation. This is the focus of most research. Additional applications of magnetic levitation include wind turbines and the levitation of frogs (seriously).
Fanhao (Marcus) Meng fm94
Aneil Hegde ash65
Nicholas Lee nsl7
Brandon Kelsey bsk35
May 28, 2008
300 E. 42nd Street
New York, NY 10017
Dear Mr. Mowbray,
We are all well aware of the pollution and traffic problems plaguing many of our nation’s urban areas. To complicate matters, gas prices have risen to record highs, and a plateau is nowhere in sight. As a result, the public is clamoring for alternative transportation technologies in order to reduce consumption and spending, particularly in some of the nation’s most congested urban areas. We intend to submit an article to Popular Science magazine detailing magnetic levitation technology as a viable alternative to these pressing issues, both from a technological standpoint and a social perspective.
Our article will first explain the fundamental principals of magnetic levitation, as well their implementation in maglev transportation. We will also discuss the pros and cons of the three most prominent maglev rail technologies currently in development around the globe. One of these technologies has been implemented for commercial use in Shanghai since January 1, 2004. In our article, we will analyze the Shanghai maglev train line extensively, discussing both its benefits and its costs. There have also been recent proposals for more maglev trains around the world, specifically in Germany, Britain, and the USA. We will describe the status of these different proposals in light of various obstacles such as economic feasibility.
This article is particularly suited to your publication for a number of reasons. Popular Science magazine is geared specifically towards futuristic, cutting edge technologies that deal with today’s problems. Magnetic levitation technology fits the bill perfectly, as it appeals to the imagination, and is often associated with futuristic visions of a fast, efficient, and cost-effective transportation system. Popular Science has already featured an article on a Trans-Atlantic, depressurized tunnel that would allow a maglev train to cross the Atlantic Ocean at speeds of up to 4,000 miles per hour. While seemingly feasible, according to MIT researchers, the astronomical costs relegate this vision to wishful thinking, at least at the present time. Our article will bridge the wide gap between contemporary technology and this far-out vision by detailing the current land-based projects and initiatives to utilize maglev rail transportation all over the world.
As juniors in the College of Engineering at Cornell University, a world-class research institution, our studies in fields relevant to magnetic levitation have allowed us to insightfully evaluate these technologies. We hope that you will consider our submission, and we will gladly send you excerpts from our article for consideration. Thank you very much for your time.
/* Rough Draft Outline: */
• Eye-catching story about transportation of some sort or about riding on hovering trains in the future
• Eye-catching story mentioning problems with cities of today, saying that solving these problems would be nice
• Reasons why other solutions to problems of congestion, pollution are not being pursued or have been pursued but do not work
• Suggest a solution that lacks the problems listed above (maglev technology)
• Citations of scholars and people who agree and disagree with the use of this technology
• Technical specifications
• Discussion of current “test run” of technology in Shanghai and how the technology is safe and reliable; also, mention the successes and failures of the “shanghai project” and others
• Difficulties and concerns with implementing this technology, including cost
• Ethical concerns of maglev transportation (eminent domain, etc.)
• Other applications of magnetic levitation technology (we have sources for these as well)
• Maglev technology has existed for quite some time, but this application of it is novel
/* Rough Draft: */
In the interest of space and whatnot, I've formatted and moved our original rough draft to the files section with "Maglev Rough Draft.doc" as the filename. All of our revision comments remain here.
-Consistent units, currency
-Include miles to kilometers conversions
-Ambulence story necessary?
-add info about other maglev lines/plans
-give idea of three different technologies and how each is considered relative to each other
/* Suggestions for Editing: */
- Units (km or miles, Euros or dollars)
- ** Ambulance story too touching!? **
- Explain Shinkansen
- Explain electromagnetic wave!?
- stress that maglev is the best transportation method for mid range travels (between 2 cities moderately far apart)
- break even cost of maglev train (mention how to reduce cost in the future)
- one story for intro… another story for conclusion!?
- make sure we are not just talking about Shanghai… it's only a case study
- Visual (pictures and diagrams)
- US instead of America
- Include some quotes
Tech: making the webpage longer
The biggest, and most obvious, challenge for making a frictionless train, however, is just making the train float. According to Earnshaw’s theorem, it is theoretically impossible for an object to reach a state of stable, stationary equilibrium. However, in spite of theoretical impossibilities, there are currently three different kinds of magnetic levitation technology being developed in Germany, Japan, and the USA that circumvent Earnshaw’s theorem by using diametric materials and never floating when stationary. Although each relies on magnets and movement to levitate their trains, the technologies developed in each of these countries are unique from each other.
In Germany, the technology they have developed is called electromagnetic suspension (EMS). The basic principle relies on the attractive force of electromagnets. The bottom of the train carriage wraps around the guide rail, and uses a linear synchronous motor (LSM) to power the electromagnets pointing towards the bottom of the guide way that levitate and propel the train. There are also controllable electromagnets on the side of the carriage pointed at the guide rail as well to guide the train’s lateral movements. With this combination of magnets, the train can float 8 to 12 mm over the guide way at a standstill, and can go up to 420 km/hr with passengers. This system boasts a minimal magnetic field exposure for passengers so magnetically sensitive items would be undamaged. However, due to the very unstable nature of electromagnetic attraction, the separation between the train and the track must be constantly monitored and corrected by onboard computer systems.
In Japan, they have taken a nearly opposite approach than the Germans called electrodynamic suspension (EDS). This method relies on the repulsive force of electromagnets. The train has controllable super conducting electromagnets on the bottom of the train carriage which are cooled by onboard cryogen systems using liquid helium and liquid nitrogen. The track itself is a U-shaped with magnetized coils on the track that can levitate the train anywhere between 8 cm to 15 cm. The walls of the track are line with coils as well, and when a current is sent through these coils, they constantly alternate polarities that propel the train forward. With passengers onboard, the train can achieve speeds of 500 km/hr. Because the train can levitate so high, this system can attain higher speeds and higher payloads than other systems. Moreover, because it uses superconducting magnets, it uses significantly less energy to operate. The downside is that the train is exposed to a significant magnetic field which could be hazardous for people with pacemakers or any magnetically sensitive devices. Furthermore, the train will not levitate until it reaches a speed of roughly 60 km/hr so it has rubber wheels when the train is not going fast enough to float. The cryogen system itself could also significantly add to the already outstanding expense of building a maglev train.
Lastly, the Lawrence Livermore National Laboratory in California has created a uniquely different approach to creating maglev transportation called Inductrack. Instead of relying on active electromagnets for levitation, this particular method uses permanent magnets arranged in what is called a Halbach Array. When magnets are arranged accordingly, they create a one sided magnetic field. Both the bottom of the train carriage and the bottom of a U-shaped track are made up of such arrays of magnets lifting the train up as high as 15 cm. Although the train cannot float when stationary, it only needs to go a mere 5 km/hr (walking speed) to generate enough force to levitate. Since the train does not require electricity to levitate, the Inductrack is considered failsafe because a power outage does not mean the train will fall. The train it propelled forward exactly like the EDS system. Because of it simplicity and use of permanent magnets, it is theorized that this method will combat the expensive costs of other maglev systems. This method is still in the testing phase, and has not been tested as extensively as the other methods have been. The only draw back as of right now is that the train will require auxiliary wheels or platform on the track when the train is stationary.
All three systems certainly have there advantages and disadvantages. The German EMS system is already being commercially used, but Japan’s EDS system could be implemented anytime now. And although new to the maglev scene, the Inductrack cannot be dismissed so easily. It is far too early to tell which technology will come out on top.