Magnetic Levitation for Transportation
By Christopher Muller - January 23, 1998 |
"We may perhaps learn
to deprive large masses of their gravity and give them
absolute levity, for the sake of easy transport."
-
Benjamin Franklin |
Note: This document was published in January
1998 as a 10th grade research paper. This document may be linked to or cited in
original research, but may not be copied in whole or in part via print or
electronic media. For links to other maglev resources, please see
RailServe.com's Monorails &
Maglev Page.
The need for fast and reliable
transportation is increasing throughout the world.
High-speed rail has been the solution for many countries.
Trains are fast, comfortable, and energy-efficient. The
United States is years behind European countries in
high-speed rail research and development. Meanwhile, in
Germany and Japan, magnetic levitation may be an even
better solution.
Maglev research and development began
in Germany and Japan during the early 1970's. After
laboratory tests in both countries, a test track was
constructed in Japan during the mid-1970's and in Germany
during the mid-1980's.
The construction of a 7-km test track began in
Miyazaki Prefecture in Japan in 1975 and was completed in
April of 1977. Test runs of the ML-500 began on the
Miyazaki Test Track in July of 1977 and a 517 km/hour run
was attained in December 1979. Two-car train sets began
testing in 1981 and three-car train sets in 1986. The
manned two-vehicle train MLU001 reached a speed of 400.8
km/hour in 1987. In 1990, the Minister of Transport of
Japan authorized construction of the Yamanashi Maglev
Test Line. It was to be the final test to confirm the
practicality of maglev. The 42.8 km line between
Sakaigawa and Akiyama of Yamanashi Prefecture opened in
1996 and the first running test of the MLX01 was in April
of 1997. (RTRI, On-line)
Germany was testing their Transrapid 07 maglev at the
TVE (Transrapid Versuchsanlage im Emsland) test track
between Nordschleife and Südschleife. Both test vehicles
have traveled more than 400,000 km on the test track as
of December 1996. The longest nonstop test has been 1,674
km in May of 1993. In June of the same year, the
Transrapid 07 set a new maglev speed record of 450
km/hour. In 1991, Germany's government certified the
operation of the first maglev train for the public. A
maglev route was to be constructed between Hamburg and
Berlin.
In the United States, scientists James R. Powell and
Gordan T. Danby patented the first design for magnetic
levitation trains in 1969. In 1970, the United States
Federal Railroad Administration studied high-speed ground
transportation. Little maglev research was accomplished
in the United States and in 1986, the government stopped
all funding toward maglev technology. Four years later,
the United States Federal Government and the Federal
Railroad Administration began to officially support
maglev technology. (Lotti-Chun, On-line) They began the
National Maglev Initiative in 1990, a cooperative effort
of the U.S. Department of Transportation, the U.S. Army
Corps of Engineers, and the U.S. Department of Energy.
The purpose of the initiative was to evaluate possible
improvements for intercity transportation with magnetic
levitation. The tasks included "planning, analyzing,
and assessing maglev technology" to make it a viable
option for future transportation. The initiative should
also determine the role that the Federal Government
should have in the development of maglev systems.
Significant effort has been devoted to the understanding
of maglev's technical and market potential, however the
key issue is whether such research and development
warrants federal investment. The Intermodal Surface
Transportation Efficiency Act of 1991 offered more
support by recognizing the goals of future transportation
systems. Section 1036 of the Act established a Maglev
Prototype Development Program which specified the
requirements for the design and construction of a U.S.
maglev system. (University of Alabama in Huntsville,
On-line)
The support and guidance systems of German magnetic
levitation are based on the attractive powers between
electromagnets on the vehicle and reaction plate rails on
the underside of the guideway. (Lotti-Chun, On-line) The
levitation and guidance magnets are controlled
individually. An electronic control system keeps the
vehicle levitating at a constant distance of 10 mm from
its guideway. The propulsion and braking systems are
based on a rotating electric motor with a split
stationary core (stator). The vehicle is then propelled
by the traveling magnetic field which is created with
support magnets serving as the exciters. The energy flow
is reversed to brake the vehicle without any contact to
the guideway. This method of propulsion requires the
motor to be installed on the guideway rather than on the
vehicle. Unlike conventional transportation systems in
which a vehicle has to carry the total power needed for
the most demanding sections, the power of the maglev
motor is dependent on the local conditions such as flat
or uphill grades. The linear induction motor installed in
the guideway is divided into sections. Power is only
supplied to sections where a vehicle is currently
located. This method conserves energy and prevents safety
concerns because all vehicles in a section of track must
be traveling at the same speed in the same direction. The
power for the German Transrapid is supplied from
Germany's 110 kV national grid system. Separate
substations provide the power independently to each side
of the guideway motor. The placement of these substations
is dependent on local route conditions. The support and
guidance systems and the onboard power is supplied via
linear generators in the support magnets resulting in an
entirely contactless technology. If the national grid
power supply fails, onboard batteries which are powered
during the journey will provide power to levitate the
vehicle until it reaches the next terminal. If the next
terminal is too far away, the vehicle is stopped at the
next power station. Braking is supplied by the onboard
batteries to slow the vehicle to 10 km/hour. The vehicle
is then lowered onto skids and stops after a few meters.
The skids are coated with a special material to create
low friction while sliding on a steel surface. There is
no reason to leave the vehicle for such a motor failure.
The heat generated by the friction will melt a thin layer
of ice when running in winter conditions. The materials
used to construct maglev vehicles are non-combustible,
poor transmitters of heat, and able to withstand fire
penetration. In the unlikely event that a fire and power
loss occurred simultaneously, the vehicle is
automatically slowed down so that it stops at a
predefined emergency power station. Research has shown
that the German Transrapid is about 20 times safer than
airplanes, 250 times safer than conventional railroads,
and 700 times safer than automobile travel. Despite the
speeds up to 500 km/hour, passengers can move about
freely in the vehicles at all times. Maglev vehicles
cannot be derailed because they surround the guideway.
Collision is impossible because there will be no
intersections and other transportation systems will cross
at different levels. A collision between two maglev
trains is nearly impossible because the linear induction
motors prevent trains running in opposite directions or
different speeds within the same power section. There is
not a solution against all vandalism and sabotage,
however many precautions have been taken. (Thyssen,
On-line)
Japanese maglev development is similar to the German
Transrapid in many ways but uses a different principle of
levitation, guidance, and propulsion. Instead of
surrounding the guideway as the German Transrapid does,
Japan's maglev vehicles are enclosed by the guideway on
the bottom and part way up the sides. (RTRI, On-line)
They start on pneumatic wheels until reaching a speed of
about 100 km/hour before the electromagnetic force
levitates the vehicle. (China Daily, On-line) Levitation
coils are installed on the sidewalls of the guideway.
Superconducting magnets are installed on the vehicles
several centimeters below the center of these guideway
coils. When the onboard magnets pass the coils at
high-speed, an electric current is induced in the coils
and they serve as electromagnets. The forces then push
the superconducting magnet upwards and levitate the
vehicle. The coils on either sidewall of the guideway
face each other and are connected under the guideway to
create a loop. The electric current changes in the loop
result in attracting and repulsive forces that keep the
vehicle in the center of the guideway. The propulsion
coils on the sidewalls of the guideway are energized by a
three-phase alternating current from a local substation.
The shifting magnetic field which is created attracts and
pushes the onboard superconducting magnets. The maglev
vehicle is then propelled along the guideway. (RTRI,
On-line)
The guideway, or track, that the maglev trains run on
can be raised above the ground or be at ground level. The
elevated guideway for Germany's Transrapid is normally 31
meters tall and the ground level guideway is normally six
meters tall. This flexibility plus the ability for
substantially sharper turns and steeper grades than
railroads allow maglev guideways to be located in many
different conditions. As with conventional railroads,
trains are made up of several individual vehicles coupled
together. The smallest train requires two vehicles and
the maximum length is only determined by the length of
station platforms, approximately ten sections. This
enables trains to be constructed depending upon demand
and the frequency increased when needed. Germany's
proposal for the Berlin to Hamburg route is to use six
section trains with trains every ten to fifteen minutes.
The end sections of a maglev train can contain between 56
and 110 seats depending upon the density of the seating
layout. Center sections can contain between 64 and 140
seats. Neither the number of seats per section nor the
number of sections comprising a train affect the
performance of a maglev train. The high speeds of a
maglev system make it suitable for transporting urgent
goods with container sections. These container sections
can form their own trains or be coupled with passenger
sections to form "mixed-traffic" trains. During
peak hours, freight trains sharing a passenger route will
have long journey times because they will often have to
wait in sidings for passenger trains to pass. Because of
this problem, German maglev research is investigating the
possibility of exclusive passenger routes and exclusive
freight routes. (Thyssen, On-line)
Conventional railroads have achieved speeds above 500
km/hour during special laboratory speed tests, yet their
normal operating speed is below 300 km/hour. Maglev
vehicles are designed for operating speeds of up to 500
km/hour. Besides the speed improvements over other
methods of transportation, maglev trains have many
benefits at slower speeds too. Maglev trains experience
lower energy consumption, less wear, lower noise levels,
and much faster acceleration without affecting passenger
comfort. Maglev trains can accelerate from 0 to 300
km/hour within 5 km compared to the German ICE high-speed
train which requires about 30 km to reach the same speed.
Because of these advantages, maglev trains are planned
for three areas of transportation: local connections such
as airport links; medium-distance inter-city connections;
and long-distance national and international connections.
(Thyssen, On-line)
Even with much faster journey times, comfort was a key
consideration during maglev development. There are no
jolts during acceleration, braking, or passing at any
speed. High pressure fluctuations occur in tunnels and
when passing opposing traffic. Extensive measurements,
computer models, and experience from high-speed rail have
resulted in an advanced technology for keeping the
vehicles pressure-tight. A variety of business services
and entertainment provide passengers with an even greater
comfort than high-speed rail travel. (Thyssen, On-line)
A major advantage of conventional rail systems versus
other methods of transportation is their ability to
operate in almost all weather conditions. Maglev systems
are even better prepared for icy conditions because they
do not require overhead power lines nor pantographs -
parts that are subject to freezing on conventional
railroads. The guidance and propulsion components are
mounted below the guideway where they are protected from
ice and driving snow. Snow will rarely accumulate on the
guideway because of the frequency of trains and the wind
that will easily remove it from elevated sections. The
gap of 150 mm between the bottom of the vehicle and the
top of the guideway allows operation even if snow builds
up on the guideway. In especially poor weather
conditions, snow clearance vehicles can be deployed to
clear the guideway. (Thyssen, On-line)
As well as the many other positive effects of maglev,
maglev trains are more environmentally-friendly than
alternative forms of transportation. They operate at
lower noise levels, consume less energy, require little
land for the guideway, and release low magnetic fields.
Noise is reduced by the contactless technology used and
air pollution is reduced because of no emissions of
exhaust gasses. A maglev train at a distance of 25 m and
speed of 250 km/hour results in vibrations, or
oscillations, below the "human threshold of
perception" (KB value of 0.1). At a distance of one
meter from the side of a maglev train running at 350
km/hour, the wind speed is only 8 km/hour. Less land is
required for both the ground-level and elevated guideway
and leaves the ground beneath the elevated guideway
suitable for other purposes such as agriculture and
traffic. In areas utilizing a ground-level guideway,
there is still enough clearance for small animals and
microorganisms to pass underneath so there will be little
effect on the environment. This guideway construction
also eliminates animal collisions that frequently occur
with roadways. Unlike conventional railroads, a maglev
guideway does not dissect the landscape. The landscape
requires fewer changes and does not have to be free of
all natural growth as they do for conventional railroads.
Maglev trains release no pollution into the ground they
run above nor do they affect local water. Raft
foundations will be used for most guideway supports which
are not even as deep as the basement of normal houses. A
well-developed construction plan will result in less
damaging effects during construction than during that of
conventional railroads and roads. Maglev routes will be
grouped with existing transportation wherever possible.
The German Transrapid releases an extremely low magnetic
field. The magnetic field, even inside a passenger
compartment, is considerably less than that of a hair
dryer, toaster, or electric sewing machine. It will
therefore have no negative influence on cardiac
pacemakers or magnetic cards such as credit cards.
(Thyssen, On-line)
The cost of making the guideway is a high percentage
of the total investment for a maglev system. These costs
are no higher than those of other high-speed rail systems
and the comparison looks even better for maglev when the
terrain becomes difficult. Many of the tunnels,
embankments, and cuttings necessary for roads and
railroads are avoided because maglev guideways can be
easily adapted to the topography. (Thyssen, On-line)
The operating costs of a maglev system are
approximately half that of conventional long-distance
railroads. There is no friction because of the
contactless technology, resulting in very little
mechanical wear. The guideway receives little pressure
because the weight of each maglev vehicle is not
transferred to the guideway at specific points like the
axles of conventional trains. Energy consumption is lower
per seat than other comparable means of transportation
and faster turnaround times mean fewer vehicles and
operating staff are required. (Thyssen, On-line)
Germany is the furthest into their development efforts
and closest to beginning construction of a commercial
maglev route. Planning permission for an initial section
of the Berlin to Hamburg line is expected by the end of
1998. Construction will then begin immediately and the
final section should be approved by the end of 1999.
After five years of construction, the route should be
completed in 2004. The Transrapid can then begin
operation over the 292-km route in 2005. The journey time
from Lehrter Station in Berlin to Hamburg Central Station
will be a maximum of 60 minutes. Transrapid trains will
run in both directions every 10 to 15 minutes during peak
times. The two terminals will be closely integrated with
other intercity services and local transportation. Nearly
two-thirds of the route will follow roadways with other
parts following existing railroads and power lines. More
than half of the route, 161 km, will run at ground level.
This maglev proposal is half-owned by the Federal
Government and half-owned by private industry. (Thyssen,
On-line)
In Japan, the Central Japan Railway Company (JR Tokai)
is leading their maglev project. They believe that
conventional railroad technology has reached its peak
performance. Japan currently has research and development
into many applications of superconductors including the
Superconducting Generator (Super GM), superconducting
storage devices, and the magnetic levitating train. Their
government's budget for superconductivity research in
1996 was 20 trillion yen (approximately $180 billion US).
Early reports propose a maglev route from Tokyo to Osaka
to be completed by 2005.
The United States, which was once a leader in
transportation including railroads, has spent years
debating the possibility of high-speed rail and maglev.
Much of the research and proposals have been done by
organizations such as the High-Speed Rail/Maglev
Association. Some airlines including USAir have a
positive interest in the development of maglev. The U.S.
government has supported airlines but ignored most
proposals for high-speed rail and maglev until the past
couple of years. The poor condition of Amtrak has created
a public feeling that railroads cannot be successful in
the United States. High-speed rail supporters believe the
contrary is true because of the metropolises that are
spread across the United States. There has also been a
public idea that the airline industry is private
enterprise and receives no government subsidy. In
reality, the airline industry receives billions of
dollars of subsidies each year. In the process, Amtrak
has lost much of their funding and service cutbacks have
been the result. There has been little improvement in
U.S. rail travel during the past couple of decades. Many
European countries have profitable national railroad
networks with millions of dollars in profits each year.
Few will argue that high-speed rail and maglev can
alleviate many of America's transportation problems. The
operational costs are cheaper than the current rail
system. The main issue is now the investment costs to
build such a transportation network. Private funding from
investors is plentiful for high-speed rail and maglev
development. The Channel Tunnel became the largest
privately financed engineering project in history with an
expense of $14 billion. As America's transportation
problems grow worse every year, the public realization of
the importance of high-speed rail and maglev will grow.
Amtrak's testing of European high-speed rail technology
is the furthest that actual testing has gotten in the
United States. Many see the high-speed rail plans
developed by Amtrak to be a very limited success, and
some high-speed rail advocates see its current drawbacks.
Because of the poor state of current railroad track, the
new high-speed rail that Amtrak is investigating will
result in minimal performance improvements. The public
may view this as the limit to high-speed rail's
capability.
In conclusion, while America appears to be many years
from the first maglev demonstration, this practical form
of high-speed transportation will soon be a reality in
Germany and Japan. High-speed rail and maglev advocates
hope that Germany's Transrapid maglev system will set the
stage for new maglev development projects around the
world.
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