Amaglev train floats about 10mm above the guideway on a magnetic field （磁場）. It is propelled （推進(jìn)） by the guideway itself rather than an onboard （機(jī)載的）engine by changing magnetic fields. Once the train is pulled into the next section the magnetism（磁性） switches2 so that the train is pulled on again. The Electro-magnets（電磁體） run the length of the guideway.

The primary（主要的）advantage is maintenance3. Because the train floats along there is no contact with the ground and therefore no need for any moving parts. As a result there are no components4 that would wear out. This means in theory trains and track would need no maintenance at all.The second advantage is that because maglev trains float， there is no friction（摩擦力）. Note that there will still be air resistance（空氣阻力）. A third advantage is less noise， because there are no wheels running along there is no wheel noise. However noise due to air disturbance （攏亂）still occurs5. The final advantage is speed， as a result of the three previous listed it is more viable6 for maglev trains to travel extremely fast， ie 500km/h.

Maglev guide paths are bound to（一定的） be more costly than conventional（常規(guī)的）steel railways.The other main disadvantage is lack with existing infrastructure（基礎(chǔ)設(shè)施）. The fact that a maglev train will not be able to continue beyond its track may seriously hinder7 its usefulness.

注釋：

1．maglev n．磁力懸浮火車

2．switch vi．改變，轉(zhuǎn)變

3．maintenance n．維修，養(yǎng)護(hù)

4．component n．(尤指機(jī)動車的)零件，部件

5．occur vi 存在，出現(xiàn)

6．viable adj.切實(shí)可行的，可實(shí)施的

7．hinder vt.阻礙，妨礙

磁懸浮列車懸浮在處于磁場中的導(dǎo)軌上方10毫米處。它是通過磁場的變化由導(dǎo)軌本身來推動，而非車載的發(fā)動機(jī)。一旦列車被牽引進(jìn)入下一個(gè)區(qū)域，磁性即發(fā)生轉(zhuǎn)換，它又會繼續(xù)被拉動。導(dǎo)軌的長度就是電磁體伸展的長度。

磁懸浮列車最大的優(yōu)點(diǎn)在于維修保養(yǎng)。由于列車是懸浮著前進(jìn)的，和地面沒有接觸，因此它不需要什么運(yùn)轉(zhuǎn)的零件，從而也就沒有什么部件會發(fā)生損耗。這就意味著從理論上來說，列車和軌道都根本不需要維修保養(yǎng)。第二個(gè)優(yōu)點(diǎn)是：因?yàn)榱熊噾腋≈簿蜎]有摩擦力。需要注意的是，空氣阻力依然存在。第三個(gè)優(yōu)點(diǎn)是噪音小。因?yàn)闆]有滾動的車輪，也就不會由此產(chǎn)生噪音。但是由于空氣的阻礙，還是會發(fā)出噪音。最后一個(gè)優(yōu)點(diǎn)是速度。由于前面所述三個(gè)原因，磁懸浮列車更能達(dá)到極快的行駛速度，即每小時(shí)500公里。

磁懸浮列車的導(dǎo)軌肯定要比常規(guī)的火車鋼軌貴得多。它還有一個(gè)主要的劣勢就是不能與現(xiàn)有的基礎(chǔ)設(shè)施相連通。磁懸浮列車一旦離開導(dǎo)軌就動不了，這可能會嚴(yán)重阻礙它實(shí)用性的發(fā)揮。