ABSTRACT

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 research on magnetic train which called maglev train was started in the beginning of the 1990 century. This concept lay dormant for about60 years. Then Japanese started their research on maglev train in the beginning of 1970 & constructed their first test line in 1997. German also started their research on maglev train in early 1970. It took them ten years to complete their first test line.
The train works on the principle of electromagnetic effect. In this there is no friction between the train and track. The electromagnet on the underside of train pulls it up to the ferromagnetic stator on the track & levitates the train. The magnet on the side keeps the train from side to side. A computer changes the amount of current to keep the train 1 cm from the track. This means there is no friction between track & train.
As it is high speed train compare to other types of train also noise level due to this train very less & energy consume is less, it is very convenient & beneficial to use.

CHAPTER 1:-INTRODUCTION

1.1 History:-
Magnetic levitation is the latest in transportation technology and has been the interest of many countries around the world. The idea has been around since 1904 when Robert Goddard, an American Rocket scientist, created a theory that trains could be lifted off the tracks by the use of electromagnetic rails. Many assumptions and ideas were brought about throughout the following years, but it was not until the 1970 that Japan and Germany showed interest in it and began researching and designing.

1.2 Concept:-
The motion of the Maglev train is based purely on magnetism and magnetic fields. This magnetic field is produced by using high-powered electromagnets. By using magnetic fields, the Maglev train can be levitated above its track, or guide way, and propelled forward. Wheels, contact with the track, and moving parts are eliminated on the Maglev train, allowing the Maglev train to essentially move on air without friction.
A brief review of magnets will help explain how maglev (magnetic levitation) trains work. Every magnet has a north pole and a south pole. Similar poles of two magnets repel each other; opposite poles attract each other. These principles govern the levitation of maglev trains.
Permanent magnets are always magnetic. Electromagnets are magnetic only when an electric current flows through them. The north and south poles of an electromagnet are related to the direction of the current. If the direction of the current is reversed, the poles are reversed.
In maglev’s that levitate by magnetic repulsion, the train lies over the guide way. Magnets on top of the guide way are oriented to repel similar poles of magnets in the bottom of the maglev. This pushes the train upward into a hovering position. This system is designed for maglev’s that contain groups of extremely powerful superconducting electromagnets. These magnets use less electricity than conventional electromagnets, but they must be cooled to very low temperatures—from −269 degrees Celsius to −196 degrees Celsius.
In maglev’s that levitate by magnetic attraction, the bottom of the train wraps around the guide way. Levitation magnets on the underside of the guide way are positioned to attract the opposite poles of magnets on the wraparound section of the maglev. This raises the train off the track. The magnets in the guide way attract the wraparound section only strongly enough to raise the train a few centimetres into a “floating” position. The wraparound section does not touch the guide way. (Imagine a C-shaped bracelet floating around your wrist without touching it.)

To picture how a maglev train is propelled forward, think of three bar magnets lined up on the floor. The magnet in front is pulling with an attracting (opposite) magnetic pole and the magnet in back is pushing with a repulsing (similar) magnetic pole. The magnet in the middle moves forward. A maglev's guideway has a long line of electromagnets. These pull the train from the front and push it from behind. The electromagnets are powered by controlled alternating currents, so they can quickly change their pull and push poles, and thus continually propel the train forward.

CHAPTER 2:- PRINCIPLE, CONSTRUCTION & WORKING

2.1Principle:- Maglev trains are trains which are suspended, guided and propelled (moved forward) by magnetic forces. The track of the maglev train is called the guide-way. Working of the maglev trains can be studied under the following * Levitation * Propulsion * Guidance Principle of magnetic levitationThe “8” figured levitation coils are installed on the sidewalls of the guideway. When the on-board superconducting magnets pass at a high speed about several centimeters below the center of these coils, an electric current is induced within the coils, which then act as electromagnets temporarily. As a result, there are forces which push the superconducting magnet upwards and ones which pull them upwards simultaneously, thereby levitating the Maglev vehicle. | | Principle of lateral guidanceThe levitation coils facing each other are connected under the guideway, constituting a loop. When a running Maglev vehicle, that is a superconducting magnet, displaces laterally, an electric current is induced in the loop, resulting in a repulsive force acting on the levitation coils of the side near the car and an attractive force acting on the levitation coils of the side farther apart from the car. Thus, a running car is always located at the center of the guideway. | | Principle of propulsionA repulsive force and an attractive force induced between the magnets are used to propel the vehicle (superconducting magnet). The propulsion coils located on the sidewalls on both sides of the guideway are energized by a three-phase alternating current from a substation, creating a shifting magnetic field on the guideway. The on-board superconducting magnets are attracted and pushed by the shifting field, propelling the Maglev vehicle. |

Figure:- Principle of maglev train

2.2 Construction & Working:-

Figure:- Construction of Maglev Train

The guide way for Maglev systems is made up of magnetized coils, for both levitation and propulsion, and the stator packs. An alternating current is then produced, from the large power source, and passes through the guide way, creating an electromagnetic field which travels down the rails. As defined by the Encarta Online dictionary, an alternating current is a current that reverses direction. The strength of this current can be made much greater than the normal strength of a magnet by increasing the number of winds in the coils. The current in the guide way must be alternating so the polarity in the magnetized coils can change. The alternating current allows a pull from the magnetic field in front of the train, and a push from the magnetic field behind the train. This push and pull motion work together allowing the train to reach maximum velocities well over 300 miles per hour.
In the construction of Maglev train consist of three basic systems:- I. Magnetic levitation system II. Propulsion system III. Lateral guidance system

2.2.1 MAGNETIC LEVITATION SYSTEM:-

Magnetic levitation means to rise and float in air. The Maglev system is made possible by the use of electromagnets and magnetic fields. The basic principle behind Maglev is that if you put two magnets together in a certain way there will be a strong magnetic attraction and the two magnets will clamp together. This is called "attraction". If one of those magnets is flipped over then there will be a strong magnetic repulsion and the magnets will push each other apart. This is called "repulsion". Now imagine a long line of magnets alternatively placed along a track. And a line of alternatively placed magnets on the bottom of the train. If these magnets are properly controlled the trains will lift of the ground by the magnetic repulsion or magnetic attraction.On the basis of this principle, Magnetic Levitation is broken into two main types of suspension or levitation,
1. Electromagnetic Suspension.
2. Electrodynamics Suspension.

2.2.1.1 ELECTROMAGNETIC SUSPENSION SYSTEM (EMS)

In current electromagnetic suspension (EMS) systems, the train levitates above a steel rail while electromagnets, attached to the train, are oriented toward the rail from below. The system is typically arranged on a series of C-shaped arms, with the upper portion of the arm attached to the vehicle, and the lower inside edge containing the magnets. The rail is situated between the upper and lower edges. Magnetic attraction varies inversely with the cube of distance, so minor changes in distance between the magnets and the rail produce greatly varying forces. These changes in force are dynamically unstable – if there is a slight divergence from the optimum position, the tendency will be to exacerbate this, and complex systems of feedback control are required to maintain a train at a constant distance from the track, (approximately 15 millimeters (0.59 in). The major advantage to suspended maglev systems is that they work at all speeds, unlike electro dynamic systems which only work at a minimum speed of about 30 km/h (19 mph). This eliminates the need for a separate low-speed suspension system, and can simplify the track layout as a result. On the downside, the dynamic instability of the system demands high tolerances of the track, which can offset, or eliminate this advantage. Laith waite, highly skeptical of the concept, was concerned that in order to make a track with the required tolerances, the gap between the magnets and rail would have to be increased to the point where the magnets would be unreasonably large.

2.2.1.2 ELECTRODYNAMIC SUSPENSION SYSTEM

In electro-dynamic suspension (EDS), both the guide way and the train exert a magnetic field, and the train is levitated by the repulsive and attractive force between these magnetic fields. In some configurations, the train can be levitated only by repulsive force. In the early stages of JR-Maglev development in Miyazaki test track, a purely repulsive system was used instead of the later repulsive and attractive EDS system. There is a misconception that the EDS system is purely a repulsive one, but that is not true. The magnetic field in the train is produced by either superconducting magnets (as in JR–Maglev) or by an array of permanent magnets. The repulsive and attractive force in the track is created by an induced magnetic field in wires or other conducting strips in the track. A major advantage of the EDS maglev systems is that they are naturally stable – minor narrowing in distance between the track and the magnets creates strong forces to repel the magnets back to their original position, while a slight increase in distance greatly reduces the repulsive force and again returns the vehicle to the right separation. In addition, the attractive force varies in the opposite manner, providing the same adjustment effects. No feedback control is needed. E D S systems have a major downside as well. At slow speeds, the current induced in these coils and the resultant magnetic flux is not large enough to support the weight of the train. For this reason, the train must have wheels or some other form of landing gear to support the train until it reaches a speed that can sustain levitation. Since a train may stop at any location, due to equipment problems for instance, the entire track must be able to support both low-speed and high-speed operation. Another downside is that the EDS system naturally creates a field in the track in front and to the rear of the lift magnets, which acts against the magnets and creates a form of drag. This is generally only a concern at low speeds This is one of the reasons why JR abandoned a purely repulsive system and adopted the sidewall levitation system. at higher speeds the effect does not have time to build to its full potential and other forms of drag dominate

2.2.2 PROPULSION SYSTEM

Electro-dynamic Propulsion is the basis of the movement in a Maglev system. The magnet will repel the north pole of a magnet while it attracts the south pole of a magnet. Likewise, the south pole of a magnet will attract the north pole and repel the south pole of a magnet. It is important to realize these three major components of this propulsion system.

The Maglev system does not run by using a conventional engine or fossil fuels. The interaction between the electromagnets and guide way is the actual motor of the Maglev system. To understand how Maglev works without a motor, we will first introduce the basics of a traditional motor. A motor normally has two main parts, a stator and a rotor. The outer part of the motor is stationary and is called the stator. The stator contains the primary windings of the motor. The polarity in the stator is able to rapidly change from north and south. The inner part of the motor is known as the rotor, which rotates because of the outer stator. The secondary windings are located within the rotor. A current is applied to the secondary wingings of the rotor from a voltage in the stator that is caused by a magnetic force in the primary windings. As a result, the rotor is able to rotate.
Now that we have an understanding of how motors work, we can describe how Maglev uses a variation on the basic ideas of a motor. Although not an actual motor, the Maglev propulsion system uses an electric synchronous motor or a linear synchronous motor. The Maglev system works in the same general way the compact motor does, except it is linear, meaning it is stretched as far as the track goes. The stators of the Maglev system are usually in the guiderails, whereas the rotors are located within the electromagnetic system on the train. The sections of track that contain the stators are known as stator packs. This linear motor is essential to any Maglev system.

2.2.3 Lateral Guidance System:-

The Lateral guidance systems control the train 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 Mag-Lev 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.
The lateral guidance system used in the Japanese electro dynamic suspension system is able to use one set of four superconducting magnets to control lateral guidance from the magnetic propulsion of the null flux coils located on the guide ways of the track. 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. 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.

The lateral guidance system found in the German transrapid system (EMS) is similar to the Japanese model. In a combination of attraction and repulsion, the Maglev train is able to remain centered on the railway. Once again levitation coils are used to control lateral movement in the German MagLev suspension system. The levitation coils are connected on both sides of the guideway and have opposite poles. The opposite poles of the guideway cause a repulsive force on one side of the train while creating an attractive force on the other side of the train. The location of the electromagnets on the Transrapid system is located in a different side of the guideways. To obtain electro magnetic suspension, the Transrapid system uses the attractive forces between iron-core electromagnets and ferromagnetic rails. In addition to guidance, these magnets also allow the train to tilt, pitch, and roll during turns. To keep all distances regulated during the ride, the magnets work together with sensors to keep the train centered.

2.2.4 Maglev Track:-
The track along which the train moves is called the guide way. Both the guide way as well as the train’s undercarriage also have magnets which repel each other. Thus the train is said to levitate about 0.39 inches on top of the guide way. After the levitation is complete, enough power has to be produced so as to move the train through the guide way. This power is given to the coils within the guide way, which in turn produces magnetic fields, which pulls and pushes the train through the guide way.

Figure:- Maglev Track
The current that is given to the electric coils of the guide way will be alternating in nature. Thus the polarity of the coils will be changing in period. Thus the change causes a pull force for the train in the front and to add to this force, the magnetic field behind the train adds more forward thrust.

Application Information:-
Maglev transport is non-contact, electric powered. It does not rely on the wheels, bearings and axles common to mechanical friction-reliant rail systems.
Speeds Maglev allows higher top speeds than conventional rail, but at least experimentally, wheel-based high-speed trains have been able to demonstrate similar speeds.
Maintenance Requirements Of Electronic Versus Mechanical Systems:
Maglev trains currently in operation have demonstrated the need for nearly insignificant guide way maintenance. Their electronic vehicle maintenance is minimal and more closely aligned with aircraft maintenance schedules based on hours of operation, rather than on speed or distance traveled. Traditional rail is subject to the wear and tear of miles of friction on mechanical systems and increases exponentially with speed, unlike maglev systems. The running costs difference is a cost advantage of maglev over rail and also directly affects system reliability, availability and sustainability.
All-Weather Operations: While maglev trains currently in operation are not stopped, slowed, or have their schedules affected by snow, ice, severe cold, rain or high winds, they have not been operated in the wide range of conditions that traditional friction-based rail systems have operated. Maglev vehicles accelerate and decelerate faster than mechanical systems regardless of the slickness of the guideway or the slope of the grade because they are non-contact systems.
Backwards Compatibility: Maglev trains currently in operation are not compatible with conventional track, and therefore require all new infrastructure for their entire route, but this is not a negative if high levels of reliability and low operational costs are the goal. By contrast conventional high speed trains such as the TGV are able to run at reduced speeds on existing rail infrastructure, thus reducing expenditure where new infrastructure would be particularly expensive (such as the final approaches to city terminals), or on extensions where traffic does not justify new infrastructure. However, this "shared track approach" ignores mechanical rail's high maintenance requirements, costs and disruptions to travel from periodic maintenance on these existing lines. It is claimed by maglev advocates. that the use of a completely separate maglev infrastructure more than pays for itself with dramatically higher levels of all-weather operational reliability and almost insignificant maintenance costs, but these claims have yet to be proven in an operational setting as intense as many traditional rail operations, and ignore the difference in maglev and traditional rail initial construction costs. So, maglev advocates would argue against rail backward compatibility and its concomitant high maintenance needs and costs.

Efficiency: Due to the lack of physical contact between the track and the vehicle, maglev trains experience no rolling resistance, leaving only air resistanceand electromagnetic drag, potentially improving power efficiency.
Weight:
The weight of the electromagnets in many EMS and EDS designs seems like a major design issue to the uninitiated. A strong magnetic field is required to levitate a maglev vehicle. For the Transrapid, this is between 1 and 2 kilowatts per ton. Another path for levitation is the use of superconductor magnets to reduce the energy consumption of the electromagnets, and the cost of maintaining the field. However, a 50-ton Transrapid maglev vehicle can lift an additional 20 tons, for a total of 70 tons, which consumes between 70 and 140 kW. Most energy use for the TRI is for propulsion and overcoming the friction of air resistance at speeds over 100 mph.
Noise:
Because the major source of noise of a maglev train comes from displaced air, maglev trains produce less noise than a conventional train at equivalent speeds. However, the psychoacoustic profile of the maglev may reduce this benefit: a study concluded that maglev noise should be rated like road traffic while conventional trains have a 5–10 dB "bonus" as they are found less annoying at the same loudness level.
Energy use:
Energy for maglev trains is used to accelerate the train. Energy may be regained when the train slows down via regenerative braking". It also levitates and stabilises the train's movement. Most of the energy is needed to overcome "air drag". Some energy is used for air conditioning, heating, lighting and other miscellany.
At low speeds the percentage of power (energy per time) used for levitation can be significant consuming up to 15% more power than a subway or light rail service For short distances the energy used for acceleration might be considerable.
The power used to overcome air drag increases with the cube of the velocity and hence dominates at high speed. The energy needed per mile increases by the square of the velocity and the time decreases linearly. For example, two and half times as much power is needed to travel at 400 km/h than 300 km/h.

Comparison with conventional train:-
Maglev transport is non-contact and electric powered. It relies less or not at all on the wheels, bearings and axles common to wheeled rail systems.
Speed:
Maglev allows higher top speeds than conventional rail, but experimental wheel-based high-speed trains have demonstrated similar speeds.
Maintenance:
Maglev trains currently in operation have demonstrated the need for minimal guideway maintenance. Vehicle maintenance is also minimal (based on hours of operation, rather than on speed or distance traveled). Traditional rail is subject to mechanical wear and tear that increases exponentially with speed, also increasing maintenance.
Weather:
Maglev trains are little affected by snow, ice, severe cold, rain or high winds. However, they have not operated in the wide range of conditions that traditional friction-based rail systems have operated. Maglev vehicles accelerate and decelerate faster than mechanical systems regardless of the slickness of the guide way or the slope of the grade because they are non-contact systems.
Track:
Maglev trains are not compatible with conventional track, and therefore require custom infrastructure for their entire route. By contrast conventional high-speed trains such as the TGV are able to run, albeit at reduced speeds, on existing rail infrastructure, thus reducing expenditure where new infrastructure would be particularly expensive (such as the final approaches to city terminals), or on extensions where traffic does not justify new infrastructure. John Harding, former chief maglev scientist at the Federal Railroad Administration claimed that separate maglev infrastructure more than pays for itself with higher levels of all-weather operational availability and nominal maintenance costs. These claims have yet to be proven in an intense operational setting and do not consider the increased maglev construction costs.
Efficiency:
Conventional rail is probably more efficient at lower speeds. But due to the lack of physical contact between the track and the vehicle, maglev trains experience no rolling resistance, leaving only air resistance and electromagnetic drag, potentially improving power efficiency. Some systems however such as the Central Japan Railway Company SCMaglev use rubber tires at low speeds, reducing efficiency gains.

Weight: The electromagnets in many EMS and EDS designs require between 1 and 2 kilowatts per ton. The use of superconductor magnets can reduce the electromagnets' energy consumption. A 50-ton Transrapid maglev vehicle can lift an additional 20 tons, for a total of 70 tons, which consumes 70-140 kW. Most energy use for the TRI is for propulsion and overcoming air resistance at speeds over 100 mph.
Weight loading: High speed rail requires more support and construction for its concentrated wheel loading. Maglev cars are lighter and distribute weight more evenly.
Noise:
Because the major source of noise of a maglev train comes from displaced air rather than from wheels touching rails, maglev trains produce less noise than a conventional train at equivalent speeds. However, the psychoacoustic profile of the maglev may reduce this benefit: a study concluded that maglev noise should be rated like road traffic, while conventional trains experience a 5–10 dB "bonus", as they are found less annoying at the same loudness level.
Braking:
Braking and overhead wire wear have caused problems for the Fastech 360 rail Shinkansen. Maglev would eliminate these issues.
Magnet reliability: At higher temperatures magnets may fail. New alloys and manufacturing techniques have addressed this issue.
Control systems: No signaling systems are needed for high-speed rail, because such systems are computer controlled. Human operators cannot react fast enough to manage high-speed trains. High speed systems require dedicated rights of way and are usually elevated. Two maglev system microwave towers are in constant contact with trains. There is no need for train whistles or horns, either.
Terrain:
Maglevs are able to ascend higher grades, offering more routing flexibility and reduced tunneling.

CHAPTER 4:- ADVATAGES AND DISADVANTAGES

4.1 ADVANTAGES:-

* The main advantage is maintenance. There is no contact between the guide way and the train which lessens the number of moving parts. Thus the components that wear out is little. * Another advantage is the reduction in noise. As there are no wheels running along there is no wheel noise. However noise due to air disturbance will still be there. * The next advantage is high speed. As there are no frictional contacts, the train is prone to have more speed. * Another advantage is that the guide way can be made a lot thicker in uphill places, after stations and so on. This will help in increasing the speed of the train further. * Maglev trains are more environmentally friendly than other types of trains. In terms of energy consumption maglev trains are slightly better off than conventional trains. As there is no wheel friction with the ground, the resistive force gradually increases in the air friction. Thus the energy efficiency difference between a Magev train and a conventional train is of very small margin.

4.2 DISADVANTAGES:-

* Cost is major issue when considering maglev trains, especially since they cannot operate on the existing, conventional rails. Guideways would need to be built in order to make use of this new technology, costing approximately $8.5 billions. * The weight of the electromagnets in the EMS and EDS systems are also an issue. A very strong magnetic field is required to levitate the heavy trains, (the transrapid TRO7 weighs 45 tons) and maintaining the field constant requires a lot of energy which is expensive.

Commercial use of Maglev Trains:-
The first known commercial use of Maglev train was in the year 1984 in Birmingham, England, and the train was named Maglev itself. But due to less reliability, the train was stopped by 1994.
The most famous commercial Maglev train is the Shanghai Maglev train in Shanghai, China. The train can go in a top speed of 270 miles/hour with an average speed of 160 miles/hour.
Since these trains move on a cushion of air, there is no friction at all [except air friction]. The trains are also aerodynamically designed which enables them to reach great speeds like 300 miles/hour and so on. At 300 miles/hour you can travel from Rome to Paris in about 2 hours.

CHAPTER 5:- CONCLUSION & REFERANCES
5.1 CONCLUSION:- Railways using Maglev technology are on the horizon. They have proven to be faster than traditional railway systems that use metal wheels and rails and are slowed by friction. The low maintenance of the MagLev is an advantage that should not be taken lightly. When you have to deal with the wear and tear of contact friction you gain greater longevity of the vehicle. Energy saved by not using motors running on fossil fuels allowmore energy efficiency and environmental friendliness. Maglev will have a positive impact on sustainability. Using superconducting magnets instead of fossil fuels, it will not emit greenhouse gases into the atmosphere. Energy created by magnetic fields can be easily replenished. The track of a Maglev train is small compared to those of a conventional train and are elevated above the ground so the track itself will not have a large effect on the topography of a region. Since a Maglev train levitates above the track, it will experience no mechanical wear and thus will require very little maintenance.
Overall, the sustainability of Maglev is very positive. Although the relative costs of constructing Maglev trains are still expensive, there are many other positive factors that overshadow this. Maglev will contribute more to our society and our planet than it takes away. Considering everything Maglev has to offer, the transportation of our future and our children future is on very capable tracks.

5.2 REFERENCES:-

http://en.wikipedia.org/wiki/Maglev http://seminarprojects.com/Thread-maglev-train-full-report http://www.youtube.com/watch?v=qi1kPRfnos0 http://science.howstuffworks.com/transport/engines-equipment/maglev-train.htm http://www.maglev.net/information/ http://www.slideshare.net/iammridul/maglev http://www.eduplace.com/science/hmxs/ps/mode2/cricket/sect7cc.shtml http://www.circuitstoday.com/working-of-maglev-trains http://www.rtri.or.jp/rd/division/rd79/yamanashi/english/principle_E.html http://www.durofy.com/how-maglev-trains-work/