Magnetically Levitated Trains (MagLev)

By Amar Kumar

Usn:1pi07me019

CONTENTS1. INTRODUCTION

2. MAGNETICALLY LEVITATED TRAINS

3. TECHNOLOGY AND WORKING OF MAGLEV

4. ADVANTAGES AND DISADVANTAGES OF MAGLEV

5. ACCIDENTS AND PRECAUTIONARY MEASURES

6. SCOPE OF MAGLEV IN FUTURE

INTRODUCTIONMagnetic levitation transport , or maglev , is a form of

transportation that suspends guides and propels vehicles via electromagnetic force.

Can reach velocities comparable to turboprop and jet aircraft (500 to 581 km/h).

The principal of a Magnet train is that floats on a magnetic field and is propelled by a linear induction motor.

The highest recorded speed of a Maglev train is 581 kilometres per hour (361 mph), achieved in Japan in 2003

MLX01 maglev train at Yamanashi test track

What are MagLev trains?

MagLev uses Electromagnetic Propulsion.Trains are thrust forward by positively and negatively

charged magnets.The train floats on a cushion of air eliminating friction.

Germany and Japan are both developing maglev train technology, and both are currently testing prototypes of their trains.

The German company "Transrapid International" also has a train in commercial use.

In Germany, engineers have developed an electromagnetic suspension (EMS) system, called Transrapid.

Japanese engineers are developing a competing version of maglev trains that use an electrodynamic suspension (EDS) system

 The key difference between Japanese and German maglev trains is that the Japanese trains use super-cooled, superconducting electromagnets. 

This kind of electromagnet can conduct electricity even after the power supply has been shut off.

In the EMS system, which uses standard electromagnets, the coils only conduct electricity when a power supply is present. 

Transrapid 09 at the Emsland test facility in Germany

Technology of MagLev

There are two primary types of maglev technology:

1. Electromagnetic suspension (EMS) uses the attractive magnetic force of a magnet beneath a rail to lift the train up.

2. Electrodynamics suspension (EDS) uses a repulsive force between two magnetic fields to push the train away from the rail.

Electromagnetic suspension (EMS)

In current EMS systems, the train levitates above a steel rail while electromagnets, attached to the train, are oriented toward the rail from below. The electromagnets use feedback control to maintain a train at a constant distance from the track.

Electrodynamics suspension (EDS)

Both the rail and the train exert a magnetic field, and the train is levitated by the repulsive force between these magnetic fields.

MagLev “Guideways” or Tracks

Track repels magnets on undercarriage of train, sending the train forward.

Train levitates between 1 and 10 cm above guideway.

Guideway of MagLev test line

Beam method

In the beam method, the sidewall portion will be constituted solely of concrete beams.

The entire process from beam manufacturing to installation of the ground coils take place at the on-site factory (provisional yard).

A finished beam is transported to the work site within the guideway, to be placed on two concrete beds set up in advance there.

Panel method

In a factory set up on-site (provisional yard) the concrete panel is produced and attached with ground coils. The finished assembly is carried to the work site, where it is fixed, with 10 bolts, to the concrete sidewall erected in advance there.

Direct-Attachment Method

At the work site in the tunnels or on the bridges a concrete sidewall portion is produced. At the same site the finished sidewall is directly fitted with the ground coils. With no need for the factory or transport vehicle, this method is economically superior to the other two, but its drawback lies in that it allows only slight adjustments of individual ground coils to correct the irregularities.

SCM of Yamanashi MagLev test line(cut model)The SCM (Superconducting Magnet) is the core element of

superconducting Maglev. Two SCMs are mounted on each bogie.

The cylindrical unit at the top is a tank holding liquefied helium and nitrogen. The bottom unit is an SC coil alternately generating N poles and S poles. At one end of the tank is the integrally-attached on-board refrigerator, which serves to re-liquefy the helium gas once vaporized by regular heat absorption and external disturbances during running.

Working of MagLev

The train uses superconducting electric magnets in the vehicle to levitate and propel the train. These magnets are cooled by liquid helium or liquid nitrogen. This means that once electrified these magnets do not require additional energy.

Propulsion• An alternating current is ran through electromagnet coils on the guide

walls of the guide way. This creates a magnetic field that attracts and repels the superconducting magnets on the train and propels the train forward.

• Braking is accomplished by sending an alternating current in the reverse direction so that it is slowed by attractive and repulsive forces.

• When the alternating current is reversed, the train brakes.

• Different speeds are achieved by varying the intensity of the current.

• Only the section of track where the train is traveling is electrified.

Levitation • The passing of the superconducting magnets by figure eight

levitation coils on the side of the tract induces a current in the coils and creates a magnetic field. This pushes the train upward so that it can levitate 10 cm above the track.

• The train does not levitate until it reaches 50 mph, so it is equipped with retractable wheels.

Lateral guidance When one side of the train nears the side of the guideway, the super conducting magnet on the train induces a repulsive force from the levitation coils on the side closer to the train and an attractive force from the coils on the farther side. This keeps the train in the center.

JR-Maglev EDS suspension is due to the magnetic fields induced either side of the vehicle by the passage of the vehicles superconducting magnets.

Advantages1. Maintenance Requirements : maglev trains currently in operation have demonstrated the need for nearly insignificant guideway maintenance.

2. All-Weather Operations : Maglev trains currently in operation are not stopped, slowed, or have their schedules affected by snow, ice, severe cold, rain or high winds.

3. Efficiency : 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.

4.Very fast: maglev trains to travel extremely fast, i.e. 500km/h or 300mph.

5.Less energy consumption because no rail-track friction

6.Requires no fossil fuel which can harm the environment.

7.Less noise pollution since the train never hits the track. However noise due to air disturbance still occurs.

8.Less space: MagLev guideways and trains take up less space than conventional trains

9.Safe: A accident between two maglev trains is nearly impossible because the linear induction motors prevent trains running in opposite directions.

Disadvantages

There are several disadvantages Maglev guide paths are bound to be more costly than conventional steel railways.

The other main disadvantage is lack with existing infrastructure.

Other MagLev Applications

Disneyland’s California Adventure CoasterCalifornia Screamin’ roller coaster uses MagLev technology

to propel car from 0-55 mph in less than 5 seconds!

Other MagLev Applications

U.S. military is looking into using MagLevPossible uses could include:

Rocket launchingAircraft carrier launching padSpace craft launching

Travel Speeds

• The train can travel at about 300mph(482.8 km/h) .

• For trips of distances up to 500 miles its total travel time is equal to a planes (including check in time and travel to airport.)

• It can accelerate to 200 mph in 3 miles, so it is ideal for short jumps. (ICE needs 20 miles to reach 200 mph.)

Economics

The Shanghai maglev demonstration line cost US$1.2 billion to build.

Baltimore-Washington Maglev project gives an estimated 2008 capital costs of US$4.361 billion for 39.1 miles

China aims to limit the cost of future construction extending the maglev line to approximately $18 million per kilometer through new guideway modular manufacturing and construction techniques.

MagLev in India

Mumbai – Delhi

A maglev line project was presented to the Indian railway minister (Lalu Prasad Yadav) by an American company. A line was proposed to serve between the cities of Mumbai and Delhi, the Prime Minister Manmohan Singh said that if

the line project is successful the Indian government would build lines between other cities and also between Mumbai centre and Chhatrapati Shivaji International Airport.

Accidents with MagLev Trains:

August 11, 2006 fire

On August 11, 2006 a fire broke out on the Shanghai commercial Transrapid, shortly after leaving the terminal in Longyang.

September 22, 2006 crash

On September 22, 2006 an elevated Transrapid train collided with a maintenance vehicle on a test run in Lathen (Lower Saxony / north-western Germany). Twenty-three people were killed and ten were injured. These were the first fatalities resulting from a Maglev train accident.

MagLev is Safe:

Maglev trains have a remarkable safety record. German-type experimental maglev trains in Japan and

Vancouver Canada had carried 2.67 million paying passengers at speeds up to 191 miles per hour, with a reliability factor of 99.96%, and no accidents.

Scope in future Provided maglev can be proved to be commercially viable

(which has not yet been done) it should be a success.However if there is no existing rail network (only the case in

the USA) then it makes sense to build a maglev line.One thing is certain, there is 31932km of track in the UK,

34449km in France and 40726km Germany, no one is going to convert all of this into maglev track, conventional trains are here to stay for a long time.

Therefore, the future of Maglev holds an undisputed demand level at the global level

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