Magnets always fascinate us and a favourite topic for many physics lovers. Magnets just not have the property to attract metals but also attracted the interests of modern day scientists. The principle of magnetism is been applied many utilities in our daily life.
Ever since the issue of global warming and fossil fuels popped up, the world is looking for an alternate energy. Transportation is one of the major factors when it comes to greenhouse gases.
How about using magnets for transportation? A transport without any fuel? without any emission? Is that possible?
Maglev Transportation is the first step towards a great future. Let us learn more about it.
What is Maglev?
Maglev (derived from magnetic levitation) is a transport method that uses magnetic levitation to move vehicles without touching the ground. With maglev, a vehicle travels along a guideway using magnets to create both lift and propulsion, thereby reducing friction and allowing higher speeds.
When you were a kid, you might have tried to balance one magnet in the air using other magnets. The same basic principle is applied using electromagnetic (maglev) tracks.
The big difference between a maglev train and a conventional train is that maglev trains do not have an engine — at least not the kind of engine used to pull typical train cars along steel tracks. The engine for maglev trains is rather inconspicuous. Instead of using fossil fuels, the magnetic field created by the electrified coils in the guideway walls and the track combine to propel the train.
Comparison with conventional trains
Maglev transport is non-contact and electric powered. It relies less or not at all on the wheels, bearings and axles common to wheeled rail systems.
- Speed: Maglev allows higher top speeds than conventional rail, but experimental wheel-based high-speed trains have demonstrated similar speeds.
- Maintenance: Maglev trains currently in operation have demonstrated the need for minimal guideway maintenance. Vehicle maintenance is also minimal (based on hours of operation, rather than on speed or distance traveled). Traditional rail is subject to mechanical wear and tear that increases exponentially with speed, also increasing maintenance.
- Weather: Maglev trains are little affected by snow, ice, severe cold, rain or high winds. However, they have not operated in the wide range of conditions that traditional friction-based rail systems have operated. Maglev vehicles accelerate and decelerate faster than mechanical systems regardless of the slickness of the guideway or the slope of the grade because they are non-contact systems.
- Track: Maglev trains are not compatible with conventional track, and therefore require custom infrastructure for their entire route. By contrast conventional high-speed trains such as the TGV are able to run, albeit 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: Conventional rail is probably more efficient at lower speeds. But 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.Some systems however such as the Central Japan Railway Company SCMaglev use rubber tires at low speeds, reducing efficiency gains.
- Weight: The electromagnets in many EMS and EDS designs require between 1 and 2 kilowatts per ton. The use of superconductor magnets can reduce the electromagnets’ energy consumption. A 50-ton Transrapid maglev vehicle can lift an additional 20 tons, for a total of 70 tons, which consumes 70-140 kW. Most energy use for the TRI is for propulsion and overcoming air resistance at speeds over 100 mph.
- Weight loading: High speed rail requires more support and construction for its concentrated wheel loading. Maglev cars are lighter and distribute weight more evenly.
- Noise: Because the major source of noise of a maglev train comes from displaced air rather than from wheels touching rails, 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 experience a 5–10 dB “bonus”, as they are found less annoying at the same loudness level.
- Braking: Braking and overhead wire wear have caused problems for the Fastech 360 rail Shinkansen. Maglev would eliminate these issues.
- Magnet reliability: At higher temperatures magnets may fail. New alloys and manufacturing techniques have addressed this issue.
- Control systems: No signalling systems are needed for high-speed rail, because such systems are computer controlled. Human operators cannot react fast enough to manage high-speed trains. High speed systems require dedicated rights of way and are usually elevated. Two maglev system microwave towers are in constant contact with trains. There is no need for train whistles or horns, either.
- Terrain: Maglevs are able to ascend higher grades, offering more routing flexibility and reduced tunneling.
Comparison with aircraft
Differences between airplane and maglev travel:
- Efficiency: For maglev systems the lift-to-drag ratio 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 kilometer. However, at high cruising speeds, aerodynamic drag is much larger than lift-induced drag. Jets take advantage of low air density at high altitudes to significantly reduce air drag. Hence despite their lift-to-drag ratio disadvantage, they can travel more efficiently at high speeds than maglev trains that operate at sea level.
- Routing: While aircraft can theoretically take any route between points, commercial air routes are rigidly defined. Maglevs offer competitive journey times over distances of 800 kilometres (500 miles) or less. Additionally, maglevs can easily serve intermediate destinations.
- Availability: Maglevs are little affected by weather.
- Safety: Maglevs offer a significant safety margin since maglevs do not crash into other maglevs or leave their guideways.
- Travel time: Maglevs do not face the extended security protocols faced by air travelers nor is time consumed for taxiing, or for queuing for take-off and landing.
Despite decades of research and development, only two commercial maglev transport systems are in operation, with two others under construction. The highest recorded maglev speed is 603 km/h (375 mph), achieved in Japan by JR Central’s L0 superconducting Maglev on 2015 April,21. The Japanese trains use super-cooled, superconducting electromagnets. This kind of electromagnet can conduct electricity even after the power supply has been shut off.
Courtesy: Wikipedia, Google and Youtube