INTRODUCTIONTECHNOLOGY AND TYPESMERITS AND DEMERITSPROPULSIONLEVITATIONSTABILITYGUIDANCEEVACUATED TUBESPOWER AND ENERGYCOMPARISON WITH AIRCRAFT AND CONVENTIONALTRAINSECONOMICSEXISTING MAGLEV SYSTEMSSUMMARYREFERENCE
Maglev is the system of transportation that usesmagnetic levitation to suspend ,guide and propel thevehicles using magnets.First described by Robert Goddard, American RocketScientist, 1909 Scientific American.Later in 1937 & 1941 a series of German patents formaglev trains propelled by linear motors awarded toHermann Kemper .In the 1960s in Britain Eric Laithwaite developed afunctional maglev train.
Uses monorail track with linear motorUses magnets to reach a really high velocityFloats about 1-10cm above the guideway on a magneticfield.Propelled by the guidewayOnce the train is pulled into the next section themagnetism switches so that the train is pulled on again. The Electro-magnets run the length of the guideway.
There are 2 notable types of maglev technology:-•Electromagnetic suspension(EMS)•Electrodynamic suspension(EDS)
Electromagnets attached to the trainHas ferromagnetic stators on the trackand levitate the train.Has guidance magnets on the sidesA computer changes the amount ofcurrent to keep the train 1 cm from thetrack.Max speed -438km/hrHas on-board battery power supply.
Supercooled superconducting magnets underthe train.Levitate about 10 cm.The field in the train due to superconductingmagnets(JR-Maglev) or an array of permanentmagnets(Inductrack).The force in the track is created by inducedmagnetic field in wires or conducting strips inthe track.Naturally stable.requires no feedback.Requires retractable wheels at low speed , max speed – 522km/hr
TECHNOL MERITS DEMERITS OGYEMS •Magnetic fields inside & outside the •Constant monitoring correction vehicle are less than EDS. of separation between vehicle & •No wheels or secondary propulsion guideway using computer required systems essential. •Can attain very high •Due to inherent instability and speed.(500km/hr). corrections ,vibration issues may occur.EDS •Onboard magnets and large •Strong magnetic field makes the separation enable highest recorded train inaccessible to passengers speeds(581km/hr) and heavy load with pacemakers or storage capacity. media like hard drives and credit •Naturally stable and hence no cards. feedback control required. •Vehicle must be wheeled for low speed travel.
TECHNOLOGY MERITS DEMERITSINDUCTRACK •Failsafe suspension-No power •Requires wheels required to activate magnets. when the vehicle isSYSTEM •Can generate enough force at stopped(PERMANENT low speeds to levitate the train. •New technology , •The train can slow down on its still underMAGNET EDS) own in case of power failures. development , no •The array of permanent commercial version magnets are cost effective than or full scale system electromagnets. prototype
EMS(Linimo) systems provide levitation & propulsionusing onboard linear motor. EDS system and Transrapid systems levitate usingonboard magnets & use propulsion coils for propulsion .Cost of propulsion coils increase over long distances.
In EDS , levitation coils levitate the train 10cm above thetrack. Levitates when speed reaches 100km/hrIn EMS , stator & support magnet levitate the train 1cmabove the track. Levitates even when train is not moving.
EMS system rely on active electronic stabilisation..All EDS systems are moving systems.Since these vehicles fly,stabilisation of pitch , roll andsway is requiredIn addition to rotation , surge , sway and or heavecan be problematic.
Some systems use Null Current systemIn EDS when the vehicle is in straight line , no current flows ,When it moves off the line this creates changing flux ,generating afield that pushes and pulls it back to the line.Some systems use coils that try to remain in the null flux pointbetween repulsive magnets and reduces eddy current losses.
Some systems use the use of vactrains-maglev traintechnology used in evacuated tubes , which removesthe air drag.This increases the speed and efficiency greatly .But the passengers may suffer from the risk ofcabin depressurization in the event of a trainmalfunction.Hence require tunnel monitoring system forrepressurization
Energy for maglev trains used to accelerate the train.Also used to make the train levitate and to stabilise themovement.Main part of the energy used to overcome the air drag.For very short distances the energy for accelerating isconsiderable.But the power used to overcome the air drag increases withcube of velocity and hence dominates at high speed.
FEATURE MAGLEV TRAIN CONVENTIONAL TRAINSpeed Allow higher top Speed is limited by speeds since they the use of wheels don’t rely on for propulsion. wheels for propulsion.
Maintenance Require insignificant Rail is subjected to wear & guideway maintenance. tear due to friction Their electronic vehicle ,increases exponentially maintenance is minimal with speed. Hence more reliable This increases running cost.All weather Unaffected by snow , May encounter problemsoperation severe cold , rain or due to degradation of high winds. guideway caused by Can accelerate & weather conditions. decelate regardless of slickness of guidewayEfficiency No rolling resistance Efficiency is affected by due to lack of contact rolling resistance due to the between track & contact with the track. vehicle. This improves power efficiency.
Weight Weight of magnets in Does not use magnets many EMS and EDS is a serious issue.Noise Major source of noise Though they produce is displaced air. more loudness , they But they are found to are less annoying than more annoying at maglev noise , hence lower loudness have a 5-10 dB bonusDesign Comparisons Maglev design Design includes eliminates the need braking and overhead for braking and wires causing wear overhead wiresControl systems Requires no signalling Has a human operator systems since the to slow down or stop speed is computer the train in time. control
Many maglevs have lift-to-drag ratio that exceed that ofaircraft.But jet transport aircraft take advantage of low air densityat high altitudes to reduce drag during cruise.Airlines cannot come close to the reliability orperformance of maglev trains in all weather conditions.Maglev fares are less susceptible to the volatile priceswings in oil markets.Has significant safety margin as they are designed not tocrash into other.
The initial investment is similar to other high speedrail roads. (Maglift is $20-$40 million per mile and I-279in Pittsburg cost $37 million per mile 17 years ago.)Operating expenses are half of that of other railroads.A train is composed of sections that each contain 100seats, and a train can have between 2 and 10 sections.The linear generators produce electricity for the cabinof the train.
TESTING TRACKS120 m test track of General Atomics at San Diego , USA.Tranrapid , a German maglev company has test track at Emsland ,Germany of length 31.5km.JR-Maglev , Japan has a test track that can reach a speed of581km/hr.
IMPORTANT OPERATIONAL SYSTEMSLinimo , Japan – commercially automated urban maglevsystem commenced on March 2005.Shangai maglev train , China – EMS high speed systemstarted operation on April 2004.HML 03 – The first EMS maglev opened to public atDaejeon South Korea in 1993.
UNDER CONSTRUCTIONAMT Test Track – Powder Springs, GeorgiaApplied levitation test track – California.Beiging S1 line.PROPOSED PLANSPenang-Kuala Lampur-Singapore line -MalaysiaMelbourne Maglev ProposalMumbai – DelhiKochi metro
They consume less energy.Require no engine.Move faster than normal trains because they are not affected byground friction; their rights-of-way, meanwhile, cost about thesame to build. Incompatible with existing rail lines, unlike traditional high-speed rail.Initial cost is very high.
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