Monday, 27 September 2010

Mag Lev Trains

A new breed of trains that basically use magnets to propel themselves across set tracks.  The train uses electromagnets to levitate a train above the tracks; this means that when travelling friction is as low as possible meaning that a greater efficiency and speed can be achieved with trains reaching over 310MPH.

Pictured above is a basic composition of the maglev train and how it is attached to the tracks, as you can see electrical energy contained in the tracks that is used to propel the train. Electrical energy is used to energise the magnets and levitate the train just a quarter inch of the ground.
Once the train is levitated, power is supplied to the coils within the guide ways to create a system of magnetic fields that pull and push the train along the guide way.
 The electric current supplied to the coils in the guide way walls is constantly alternating to change the polarity of the magnetized coils. This change in polarity causes the magnetic field in front of the train to pull the vehicle forward, while the magnetic field behind the train adds more forward thrust.
an illustration that shows how the Yamanashi maglev guideway works


Ways in which the maglev can be improved
Con- 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; this will have a dramatic effect on the use of the train because many business people and ordinary passengers will need to be able to take on credit cards and electrical devices.

Possible remedy- A casing around the carriage of the train or passenger compartments could be a remedy of this problem, a protective layer of Mu-Metal, an iron nickel alloy, could provide enough protection due to its properties of dispersing low frequency magnetic fields.  It is the high permeability of mu-metal provides a low reluctance path for magnetic flux, creasing the desired effect. Further development in magnetic shielding could reducing the cost and the weight of said shielding, creasing a lighter more efficient train, that is cheaper to build. But a Mu-Metal casing might not be enough to shield from the stronger magnetic fields, and more advance materials must be developed with high permeability and lower resistance.
Con- The lack of infrastructure for maglev trains will be a major problem for the future wide spread development of the technology, the con is not so much the lack of infrastructure but the initial cost of setting it up, because the maglev has to be suspended above the ground, and they will have to run alongside existing train tracks, so space is more scarce. I think the future of maglev’s, will be high speed city links, a simple two track, going from a few pre-designated points, such as existing systems like in Shanghai.
Solution- I think the future of maglev’s, will be high speed city links, a simple two track, going from a few pre-designated points, such as existing systems like in Shanghai. This will maximise efficacy especially during rush hour, because passenger numbers will be high, and a maglev train will drastically cut commute times. The only way future developments in electrical technology will help infrastructure being built, is if new cheaper materials are developed, or cheaper ways are designed to erect and maintain the tracks.

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