Behind me stands Milsons point train
station
like all other train stations around the
world it is a vital link for
transporting people as they carry out
their daily lives;
but as we strive for a ever quicker
future, the trains that have been transporting
us for centuries are no longer able to
keep up. The problem?
Friction. The solution? Maglev. The vision
of Maglev began in the early 20th
century with two men:
Robert Goddard and Emily Bachelet. Their
dream was to develop a transistor that
was faster, safer and more reliable.
Thus, they turned to Electromagnets. Since then, China Japan and South Korea have
all joined the race to develop the fastest
Maglev systems.
But what exactly is it that allows these
trains to move so quickly?
In short, the answer lies in
electromagnetism;
however, there are currently two very
different systems of Maglev that
provide suspension in two very
different ways.
The first is called electromagnetic
suspension and is used in the current
German transrapid systems. EMS uses the
attractive forces between iron core
electromagnets and ferromagnetic rails.
Electromagnets, that have current flowing
through them, are first placed on the
underside of the carriage, which creates
a magnetic field that is attracted to
the stationary ferromagnetic reaction
rails that are installed on the
underside of the guideway. This
attraction results in a distance of just
10 millimeters between the stator and
support magnet, which allows the carriage
to hover 150 millimeters above the
top of the guideway. The train is
propelled by the support magnets on the
carriage which provide an alternating
current that works to create a series of
attractive poles and repelling poles,
resulting in forward movement.
The second system is electrodynamic
suspension and is currently used in
prototype Japanese SC maglev trains. EDS
relies on the principle of super
conductivity, whereby super
conducting materials are cooled to
extremely low temperatures. The
superconducting materials are placed on
the side of the train carriage and
interact with figure eight shaped coils on
the side of the guideway. When the coils
experience the changing magnetic field
of the superconductor's motion (as the
train moves) two currents are induced that
oppose the change in magnetic field: one
below, that creates a reactive magnetic
field that opposes the superconducting
magnet's pole,
and one above that creates a pole that
attracts it. Thus, the two forces work together to
achieve an approximate levitation of 10
centimeters above the guideway.
Propulsion is achieved by a linear
synchronous motor, consisting of
additional coils in the guideway that
provide a three-phase alternating
current. The magnetic field created by
the superconductor then interacts with
this magnetic field to propel it forward.
Now that we have explored how Magev works,
it is time to discuss exactly why it is
better.
The problem with traditional trains is
that energy is lost through friction. Maglev
trains on the other hand address this
problem by eliminating contact with the
guideway entirely. Thus, they have longer lifetimes, lower
operating costs and are able to travel
significantly faster and quieter than
traditional trains.
Furthermore, EMS trains have the added
advantage of reduced civilian exposure
to magnetic fields when compared with EDS.
EDS, on the other hand, is potentially safer, as
they do not crash immediately into the
guideway in the event of a power outage. However, they do not come without
shortcomings. For EMS systems, expensive
processing computers are needed to
ensure that the carriages do not move
too close to the guideway. For EDS
systems, the cooling of superconducting
magnets creates a significant energy
cost that decreases its economic
viability. There is no doubt that as our society
continues to grow
train stations like this will become obsolete.
Although the cost of building Maglev trains
and its accompanying infrastructure is expensive,
the speed, efficiency
and safety they provide
will ultimately become vital
as we look toward an
ever faster, ever cheaper future.
