INTRODUCTION
Magnetic levitation, maglev, or magnetic suspension is a method by which an object is
suspended with no support other than magnetic fields. The electromagnetic force is used to
counteract the effects of the gravitational force.
Earnshaw's theorem proves that using only static
ferromagnetism it is impossible to stably levitate
against gravity as required for stable equilibrium.
Earnshaw's theorem can be viewed as a
consequence of the Maxwell equations, which
do not allow the magnitude of a magnetic field in a
free space to possess a maximum. But
servomechanisms, the use of diamagnetic
materials or superconductor permit this to occur. For a particle to be in a stable equilibrium,
small perturbations ("pushes") on the particle in any direction should not break the
equilibrium; the particle should "fall back" to its previous position. This means that the force
field lines around the particle's equilibrium position should all point inwards, towards that
position. If all of the surrounding field lines point towards the equilibrium point, then the
divergence of the field at that point must be negative (i.e. that point acts as a sink).
However, Gauss's Law says that the divergence of any possible electric force field is zero in
free space. Diamagnets (which respond to magnetic fields with mild repulsion) are known to
flout the theorem, as their negative susceptibility results in the requirement of a minimum
rather than a maximum in the field’s magnitude. Stable levitation has been demonstrated for
diamagnetic objects such as superconducting pellets and live creatures. Strong
diamagnetism of superconductors allows the situation to be reversed, so that a magnet can
be levitated above a superconductor.
We set out to lift a magnet by applying a magnetic field and then stabilizing the intrinsically
unstable equilibrium with repulsive forces from a nearby diamagnetic material. Diamagnetic
levitation can be used to levitate very light pieces of pyrolytic graphite or bismuth above a
moderately strong permanent magnet. As water is predominantly diamagnetic, this
technique has been used to levitate water droplets and even live animals, such as a
grasshopper and a frog. However, the magnetic fields required for this are very high,
typically in the range of 16 teslas, and therefore create significant problems if ferromagnetic
materials are nearby.
1
MAGLEV METHODS
There are several methods to obtain magnetic levitation. The following are a few general
methods.
Mechanical constraint (Pseudo-levitation)
With a small amount of mechanical constraint for stability, pseudo-levitation is relatively
straightforwardly achieved.
If two magnets are mechanically constrained along a single vertical axis, for example, and
arranged to repel each other strongly, this will act to levitate one of the magnets above the
other.
Another geometry is where the magnets are attracted, but constrained from touching by a
tensile member, such as a string or cable.
Another example is the Zippe-type centrifuge where a cylinder is suspended under an
attractive magnet, and stabilised by a needle bearing from below.
Direct diamagnetic levitation
A live frog levitates inside a 32 mm diameter vertical bore of
a Bitter solenoid in a magnetic field of about 16 teslas at the
High Field Magnet Laboratory of the Radboud University in
Nijmegen the Netherlands.
A substance that is diamagnetic repels a magnetic field. All materials have diamagnetic
properties, but the effect is very weak, and is usually overcome by the object's
paramagnetic or ferromagnetic properties, which act in the opposite manner. Any material in
which the diamagnetic component is strongest will be repelled by a magnet, though this
force is not usually very large.
2
Earnshaw's theorem does not apply to diamagnets. These behave in the opposite manner
to normal magnets owing to their relative permeability of μr < 1 (i.e. negative magnetic
susceptibility).
Diamagnetic levitation can be used to levitate very light pieces of pyrolytic graphite or
bismuth above a moderately strong permanent magnet. As water is predominantly
diamagnetic, this technique has been used to levitate water droplets and even live animals,
such as a grasshopper and a frog. However, the magnetic fields required for this are very
high, typically in the range of 16 teslas, and therefore create significant problems if
ferromagnetic materials are nearby.
The minimum criterion for diamagnetic levitation is






, where:
χ is the magnetic susceptibility
ρ is the density of the material
g is the local gravitational acceleration (-9.8 m/s2 on Earth)
μ0 is the permeability of free space
B is the magnetic field
is the rate of change of the magnetic field along the vertical axis
Assuming ideal conditions along the z-direction of solenoid magnet:

Water levitates at

Graphite levitates at
3
Superconductors
Superconductors may be considered perfect diamagnets (μr = 0), completely expelling
magnetic fields due to the Meissner effect. The levitation of the magnet is stabilized due to
flux pinning within the superconductor. This principle is exploited by EDS (electrodynamic
suspension) magnetic levitation trains, superconducting bearings, flywheels, etc.
In trains where the weight of the large electromagnet is a major design issue (a very strong
magnetic field is required to levitate a massive train) superconductors are sometimes
proposed for use for the electromagnet, since they can produce a stronger magnetic field for
the same weight.
Diamagnetically-stabilized levitation
A permanent magnet can be stably suspended by various configurations of strong
permanent magnets and strong diamagnets. When using superconducting magnets, the
levitation of a permanent magnet can even be stabilized by the small diamagnetism of water
in human fingers.
Rotational stabilization
A magnet can be levitated against gravity when gyroscopically stabilized by spinning it in a
toroidal field created by a base ring of magnet(s). However, it will only remain stable until
the rate of precession slows below a critical threshold — the region of stability is quite
narrow both spatially and in the required rate of precession. The first discovery of this
phenomenon was by Roy Harrigan, a Vermont inventor who patented a levitation device in
1983 based upon it. Several devices using rotational stabilization (such as the popular
Levitron toy) have been developed citing this patent. Non-commercial devices have been
created for university research laboratories, generally using magnets too powerful for safe
public interaction.
4
Servomechanisms
The attraction from a fixed strength magnet decreases with increased distance, and
increases at closer distances. This is termed 'unstable'. For a stable system, the opposite is
needed, variations from a stable position should push it back to the target position.
Stable magnetic levitation can be achieved by measuring the position and speed of the
object being levitated, and using a feedback loop which continuously adjusts one or more
electromagnets to correct the object's motion, thus forming a servomechanism.
Many systems use magnetic attraction pulling upwards against gravity for these kinds of
systems as this gives some inherent lateral stability, but some use a combination of
magnetic attraction and magnetic repulsion to push upwards.
This is termed Electromagnetic suspension (EMS). For a very simple example, some
tabletop levitation demonstrations use this principle, and the object cuts a beam of light to
measure the position of the object. The electromagnet is above the object being levitated;
the electromagnet is turned off whenever the object gets too close, and turned back on
when it falls further away. Such a simple system is not very robust; far more effective control
systems exist, but this illustrates the basic idea. A practical demonstration of such system
can be seen here. Of course in the real situation the problem becomes much more complex
while the requirements of a MAGLEV suspension are difficult to achieve, i.e the
electromagnetic suspension has to support very large mass (for axample 1T) wihtin a small
air gap (in the region of mm). Also, the EMS system has to accomodate the rail
irregulatrities while follow the track gradients. Nevertheless, all these requirements can be
achieved using advance control strategies. A practical demonstration of a 25kg Electromagnetic suspension setup is shown here. The Electromagnets are suspending 5mm below
the track (rail). The control can be done using classical strategies as shown here or modern
control strategies as shown here.
EMS magnetic levitation trains are based on this kind of levitation: The train wraps around
the track, and is pulled upwards from below. The servo controls keep it safely at a constant
distance from the track.
5
Induced currents/Eddy currents
This is sometimes called ElectroDynamic Suspension (EDS).
Relative motion between conductors and magnets
If one moves a base made of a very good electrical conductor such as copper, aluminium or
silver close to a magnet, an (eddy) current will be induced in the conductor that will oppose
the changes in the field and create an opposite field that will repel the magnet (Lenz's law).
At a sufficiently high rate of movement, a suspended magnet will levitate on the metal, or
vice versa with suspended metal. Litz wire made of wire thinner than the skin depth for the
frequencies seen by the metal works much more efficiently than solid conductors.
An especially technologically-interesting case of this comes when one uses a Halbach array
instead of a single pole permanent magnet, as this almost doubles the field strength, which
in turn almost doubles the strength of the eddy currents. The net effect is to more than triple
the lift force. Using two opposed Halbach arrays increases the field even further.[3]
Halbach arrays are also well-suited to magnetic levitation and stabilisation of gyroscopes
and electric motor and generator spindles.
Oscillating electromagnetic fields
A conductor can be levitated above an electromagnet (or vice versa) with an alternating
current flowing through it. This causes any regular conductor to behave like a diamagnet,
due to the eddy currents generated in the conductor. Since the eddy currents create their
own fields which oppose the magnetic field, the conductive object is repelled from the
electromagnet.
This effect requires non-ferromagnetic but highly conductive materials like aluminium or
copper, as the ferromagnetic ones are also strongly attracted to the electromagnet
(although at high frequencies the field can still be expelled) and tend to have a higher
resistivity giving lower eddy currents. Again, litz wire gives the best results.
6
The effect can be used for stunts such as levitating a telephone book by concealing an
aluminium plate within it.
Stabilized permanent magnet suspension
In this method a repulsive magnet arrangement is used to provide lift and then any one or
combination of the above stabilisation systems are used laterally. The vertical component of
the lift magnets is stable in this arrangement, whereas the horizontal component is unstable,
but, (depending on the geometry) rather smaller, and hence somewhat easier to stabilise.
7
Application in MEGLAV VEHICLE
The main application of meglav is in meglav vehicle so while discussing magnetic levitation
it is a must to discuss the technology used in meglav vehicle. The term "maglev" refers not
only to the vehicles, but to the railway system as well, specifically designed for magnetic
levitation and propulsion. All operational implementations of maglev technology have had
minimal overlap with wheeled train technology and have not been compatible with
conventional rail tracks. Because they cannot share existing infrastructure, these maglev
systems must be designed as complete transportation systems.
Basically the there are three main forces involved in working of a meglav vehicle. All the
forces work for one goal to stably levitate a considerable mass while making it move from
one place to another.
 LEVITATION.
 PROPULSION.
 LATERAL GUIDING
LEVITATION
The levitating force is the upward thrust which lifts the vehicle in the air. It counteracts the
gravitational force and make the body float in air.
There are 3 types of levitating systems.
 For electromagnetic suspension (EMS), electromagnets in the train repel it away
from a magnetically conductive (usually steel) track.
 electrodynamic suspension (EDS) uses electromagnets on both track and train to
push the train away from the rail.
 stabilized permanent magnet suspension (SPM) uses opposing arrays of permanent
magnets to levitate the train above the rail.
Another experimental technology, which was designed, proven mathematically, peer
reviewed, and patented, but is yet to be built, is the magnetodynamic suspension (MDS),
which uses the attractive magnetic force of a permanent magnet array near a steel track to
lift the train and hold it in place.
8
ELECTROMAGNETIC SUSPENSION (EMS)
The attraction from a fixed strength magnet decreases with increased distance, and
increases at closer distances. This is termed 'unstable'. For a stable system, the opposite is
needed; variations from a stable position should push it back to the target position.
Stable magnetic levitation can be
achieved by measuring the position and
speed of the object being levitated, and
using a feedback loop which
continuously adjusts one or more
electromagnets to correct the object's
motion, thus forming a
servomechanism.
Many systems use magnetic attraction
pulling upwards against gravity for
these kinds of systems as this gives
some inherent lateral stability, but some use a combination of magnetic attraction and
magnetic repulsion to push upwards.
This is termed Electromagnetic suspension (EMS). For a very simple example, some
tabletop levitation demonstrations use this principle, and the object cuts a beam of light to
measure the position of the object. The electromagnet is above the object being levitated;
the electromagnet is turned off whenever the object gets too close, and turned back on
when it falls further away. Such a simple system is not very robust; far more effective control
systems exist, but this illustrates the basic idea. Of course in the real situation the problem
becomes much more complex while the requirements of a MAGLEV suspension are difficult
to achieve, i.e the electromagnetic suspension has to support very large mass (for example
1T) wihtin a small air gap (in the region of mm). Also, the EMS system has to accomodate
the rail irregulatrities while follow the track gradients. Nevertheless, all these requirements
can be achieved using advance control strategies. EMS magnetic levitation trains are based
on this kind of levitation: The train wraps around the track, and is pulled upwards from
below. The servo controls keep it safely at a constant distance from the track.
9
Electrodynamic suspension
In electrodynamic 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. The magnetic
field in the train is produced by either electromagnets (as in JR-Maglev) or by an array of
permanent magnets (as in Inductrack).
The repulsive force in the track is created
by an induced magnetic field in wires or
other conducting strips in the track.
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.
Onboard magnets and large margin between rail and train enable highest recorded train
speeds (581 km/h).This system is inherently stable. Magnetic shielding for suppression of
strong magnetic fields and wheels for travel at low speed are required. It can’t produce the
propulsion force. So, LIM system is required.
Fig. 9 The guideway of the electrodynamic suspension
system is installed with guidance-levitation coils.
10
Stabilized Permanent Magnet suspension
SPM maglev systems differ from EDS maglev in that they use opposing sets of rare earth
magnets (typically neodymium alloys in a Halbach array) in the track and vehicle to create
permanent, passive levitation; i.e., no power is required to maintain permanent levitation.
With no current required for levitation, the system has much less electromagnetic drag, thus
requiring much less power to move a given cargo at a given speed.
Because of Earnshaw's theorem, SPM maglev systems require a mechanism to create
lateral stability (i.e., controlling the side-to-side movement of the vehicle). One way to
provide this stability is to use a set of coils along the bottom of the magnet array on the
vehicle being levitated, which centers the vehicle over the rails by means of small amounts
of current. Because the voice coils are not needed to provide lift and there is almost no
drag, this system uses less power than other maglev systems: when the vehicle is centered
over the rails, it uses no power. As the vehicle navigates a curve, the controller moves the
vehicle to a ‘balance point’ inside the curve so that the (magnetic) centripetal pull of the
magnetic rails in the ground offset the vehicle’s (kinetic) centrifugal momentum. This
balance point varies based on the vehicle’s weight, which the controller automatically
accounts for, resulting in zero steady state power consumption.
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INDUCTRACK SYSTEM:
The inductrack guide way would contain two rows of tightly packed levitation
coils, which would act as the rails. Each of these “rails” would be lined by two Halbach
arrays carried underneath the maglev vehicle: one positioned directly above the “rail” and
one along the inner side of the “rail”. The Halbach arrays above the coils would provide
levitation while the Halbach arrays on the sides would provide lateral guidance that keeps
the train in a fixed position on the track.
The track is actually an array of electrically-shorted circuits containing insulated wire. In one
design, these circuits are aligned like rungs in a ladder. As the train moves, a magnetic field
repels the magnets, causing the train to levitate.
There are two inductrack designs. Inductrack I and II. Inductrack I is designed
for high speeds, while inductrack II is suited for slow speeds. Inductrack trains could levitate
higher with greater stability. As long as it’s moving a few miles per hour, an inductrack train
will levitate nearly an inch above the track. A greater gap above the track means that the
train would not require complex sensing systems to maintain stability. Permanent magnets
had not been used before because scientists thought that they would not create enough
levitating force. The inductrack design bypasses this problem by arranging the magnets in a
Halbach array. The magnets are configured so that the intensity of the magnetic field
concentrates above the array instead of below it which generates higher magnetic field.
12
The inductrack II design incorporates two Halbach arrays to generate a stronger
magnetic field at lower speeds. Dr. Richard post at the Livermore National Laboratory in
California came up with this concept in response to safety and cost concerns. The prototype
tests caught the attention of NASA, which awarded a contract to Dr.post and his team to
explore the possibility of using the inductrack system to launch satellites into orbit.
PROPULSION
This is a horizontal force which causes the movement of train. An EDS
system can provide both levitation and propulsion using an onboard linear motor. EMS
systems can only levitate the train using the magnets onboard, not propel it forward. As
such, vehicles need some other technology for propulsion. A linear motor (propulsion
coils) mounted in the track is one solution. Over long distances where the cost of
propulsion coils could be prohibitive, a propeller or jet engine could be used.
It requires 3 parameters.
•
Large electric power
supply
•
Metal coil lining, a
guide way or track.
•
Large magnet
attached under the vehicle.
PRINCIPLES OF LINEAR MOTOR
Its principle is similar to induction motor having linear stator and flat rotor. The
3-phase supply applied to the stator produces a constant speed magnetic wave, which
further produces a repulsive force.
13
Maglev vehicles are propelled primarily by one of the following three options:
1.A linear synchronous motor (LSM) in which coils in the guideway are excited by a
three phase winding to produce a traveling wave at the speed desired; Trans Rapid in
Germany employs such a system.
2. A Linear Induction Motor (LIM) in which an electromagnet underneath the vehicle
induces current in an aluminum sheet on the guideway.
3. A reluctance motor is employed in which active coils on the vehicle are pulsed at the
proper time to realize thrust.
LATERAL GUIDING:
Guidance or steering refers to
the sideward forces that are required to
make the vehicle follow the guideway. The
necessary forces are supplied in an exactly
analogous fashion to the suspension
forces, either attractive or repulsive. The
same magnets on board the vehicle, which
supply lift, can be used concurrently for
guidance or separate guidance magnets can be used.
14
It requires the following arrangements:
 Guideway levitating coil
 Moving magnet
Also some systems use Null Flux systems (also called Null Current systems). These use a
coil which is wound so that it enters two opposing, alternating fields. When the vehicle is in
the straight ahead position, no current flows, but if it moves off-line this creates a changing
flux that generates a field that pushes it back into line.
STABILITY:
Earnshaw's theorem shows that any combination of static magnets cannot be in a stable
equilibrium. However, the various levitation systems achieve stable levitation by violating
the assumptions of Earnshaw's theorem. Earnshaw's theorem assumes that the magnets
are static and unchanging in field strength and that permeability is constant everywhere.
EMS systems rely on active electronic stabilization. Such systems constantly measure the
bearing distance and adjust the electromagnet current accordingly. All EDS systems are
moving systems (no EDS system can levitate the train unless it is in motion).
Because Maglev vehicles essentially fly, stabilisation of pitch, roll and yaw is required by
magnetic technology. In addition translations, surge (forward and backward motions), sway
(sideways motion) or heave (up and down motions) can be problematic with some
technologies.
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Pros and cons of different technologies
Each implementation of the magnetic levitation principle for train-type travel involves
advantages and disadvantages. Time will tell us which principle, and whose implementation,
wins out commercially.
Technology
Pros
Cons
EMS
Magnetic fields inside and outside
(Electromagnetic the vehicle are less than EDS;
proven, commercially available
suspension)
technology that can attain very high
speeds (500 km/h); no wheels or
secondary propulsion system
needed
The separation between the vehicle
and the guideway must be
constantly monitored and corrected
by computer systems to avoid
collision due to the unstable nature
of electromagnetic attraction; due
to the system's inherent instability
and the required constant
corrections by outside systems,
vibration issues may occur.
EDS
Onboard magnets and large margin
(Electrodynamic) between rail and train enable
highest recorded train speeds
(581 km/h) and heavy load capacity;
has recently demonstrated
(December 2005) successful
operations using high temperature
superconductors in its onboard
magnets, cooled with inexpensive
liquid nitrogen
Strong magnetic fields onboard the
train would make the train
inaccessible to passengers with
pacemakers or magnetic data
storage media such as hard drives
and credit cards, necessitating the
use of magnetic shielding;
limitations on guideway inductivity
limit the maximum speed of the
vehicle; vehicle must be wheeled
for travel at low speeds.
Inductrack
System
Requires either wheels or track
segments that move for when the
Failsafe Suspension - no power
required to activate magnets;
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(Permanent
Magnet EDS)
Magnetic field is localized below the
car; can generate enough force at
low speeds (around 5 km/h) to
levitate maglev train; in case of
power failure cars slow down on
their own safely; Halbach arrays of
permanent magnets may prove
more cost-effective than
electromagnets
vehicle is stopped. New technology
that is still under development (as
of 2008) and as yet has no
commercial version or full scale
system prototype.
Neither Inductrack nor the Superconducting EDS are able to levitate vehicles at a standstill,
although Inductrack provides levitation down to a much lower speed. Wheels are required
for these systems. EMS systems are wheel-less.
17
complexities faced in magnetic levitation
Most of the levitation techniques have various complexities.

Many of the active suspension techniques have a fairly narrow region of stability.

Magnetic fields have no built-in damping. This can permit vibration modes to exist
that can cause the item to leave the stable region. Eddy currents can be stabilizing if
a suitably shaped conductor is present in the field, and other mechanical or
electronic damping techniques have been used in some cases.

Power and current requirements can be reasonably large to generate sufficiently
strong magnetic fields using electromagnets to lift significant mass.

Superconductors require very low temperatures to operate, often helium cooling is
employed.
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Comparison
Compared to conventional trains
Major comparative differences between the two technologies lie in backward-compatibility,
rolling resistance, weight, noise, design constraints, and control systems.
Backwards Compatibility Maglev trains currently in operation are not compatible with
conventional track, and therefore require all new infrastructure for their entire route. 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.
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.[13]
Weight The weight of the large electromagnets in many EMS and EDS designs is a major
design issue. A very strong magnetic field is required to levitate a massive train. For this
reason one research path is using superconductors to improve the efficiency of the
electromagnets, and the energy cost of maintaining the field.
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.[14][15]
Design Comparisons Braking and overhead wire wear have caused problems for the
Fastech 360 railed Shinkansen. Maglev would eliminate these issues. Magnet reliability at
higher temperatures is a countervailing comparative disadvantage (see suspension types),
but new alloys and manufacturing techniques have resulted in magnets that maintain their
levitational force at higher temperatures.
19
As with many technologies, advances in linear motor design have addressed the limitations
noted in early maglev systems. As linear motors must fit within or straddle their track over
the full length of the train, track design for some EDS and EMS maglev systems is
challenging for anything other than point-to-point services. Curves must be gentle, while
switches are very long and need care to avoid breaks in current. An SPM maglev system, in
which the vehicle permanently levitated over the tracks, can instantaneously switch tracks
using electronic controls, with no moving parts in the track. A prototype SPM maglev train
has also navigated curves with radius equal to the length of the train itself, which indciates
that a full-scale train should be able to navigate curves with the same or narrower radius as
a conventional train.
Control Systems EMS Maglev needs very fast-responding control systems to maintain a
stable height above the track; this needs careful design in the event of a failure in order to
avoid crashing into the track during a power fluctuation. Other maglev systems do not
necessarily have this problem. For example, SPM maglev systems have a stable levitation
gap of several centimeters.
Compared to aircraft
For many systems, it is possible to define a lift-to-drag ratio. For maglev systems these
ratios can exceed that of aircraft (for example Inductrack can approach 200:1 at high speed,
far higher than any aircraft). This can make maglev more efficient per kilometre. However,
at high cruising speeds, aerodynamic drag is much larger than lift-induced drag. Jet
transport aircraft take advantage of low air density at high altitudes to significantly reduce
drag during cruise, hence despite their lift-to-drag ratio disadvantage, they can travel more
efficiently at high speeds than maglev trains that operate at sea level (this has been
proposed to be fixed by the vactrain concept). Aircraft are also more flexible and can service
more destinations with provision of suitable airport facilities.
Unlike airplanes, maglev trains are powered by electricity and thus need not carry fuel.
Aircraft fuel is a significant danger during takeoff and landing accidents. Also, electric trains
emit little carbon dioxide emissions, especially when powered by nuclear or renewable
sources.
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Recent advancement
In the far future Maglev trains are hoped to be used to transport vast volumes of water to far
regions at a greater speed eliminating droughts. Far more, space is an open door to maglev
trains to propel humans and cargo into space at a lower cost. But most important is the New
York-London tunnel, which runs under the Atlantic’s water, to form the last stage of the
intercontinental highway. Scientists hope future technologies can get the train to operate at
a 6000km/h, since theoretically the speed limit is limitless. But still it’s a long way to go.
Transrapid International is developing an electromagnetic suspension system (EMS). They
have already demonstrated that it can reach 500Km/h with people on board. This speed can
get a passenger from Paris to Rome in 2 hours. The Swiss are considering a new 700km
system. The developers of these trains will most likely be connecting major cities up to
1600km away from each other, linking the busiest routes and exploiting their niche by being
the fastest mode of accessible transport. The costs of producing the guideway at the
moment still remain quite high at $10 million to $30million per mile.
If these technologies have the potential to reach 6000km/hr then why so far only 517km/hr
have been materialized? Well it is due to the fact that the speed of the vehicle is limited by
the air drag and the electromagnetic drag. Now electromagnetic drag has been overcome
by the use of Halbach array of magnets. And as for the air drag scientist are working over
the vacuum tubes for maglev vehicle but it has its own disadvantage as any defect in the
body of the vehicle would eventually put the life of people travelling. So a great work is still
to be done to overcome the air drag so as to improve the efficiency and cost efficiency.
Another area that still requires development is the development of the high temperature
superconductors. As of now the working of the superconductor needs less temperature
which is obtained by liquid nitrogen.
21