Maglev Trains
1 A few countries are using powerful electromagnets to develop high-speed trains, called maglev trains. Maglev is short for magnetic levitation 1 , which means that these trains float over a guide way using the basic principles of magnets to
replace the old steel wheel and track trains.
2 If you’ve ever played with magnets, you know that opposite poles attract and like poles repel each other2. This is the basic principle behind electromagnetic propulsion. Electromagnets are similar to other magnets in that they attract metal objects, but the magnetic pull is temporary. You can easily create a small electromagnet yourself by connecting the ends of a copper wire to the positive and negative ends of an AA—cell battery3. This creates a small magnetic field. If you disconnect either end of the wire from the battery, the magnetic field is taken away.
3 The magnetic field created in this wire-and-battery experiment is the simple idea behind a maglev train rail system. There are three components to this system: A large electrical power source, metal coils lining a guide way or track, and large guidance magnets attached to the underside of the train.
4 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 tracks4. The engine for maglev trains is rather innoticeable. Instead of using fossil fuels, the magnetic field created by the electrified coils in the guideway walls and the track combines to propel the trains5.
5 The magnetized coil running along the track, called a guideway, repels the large magnets on the train’s undercarriage, allowing the train to levitate between 1 to 10 cm above the guideway. Once the train is levitated, power is supplied to the coils within the guideway walls to create a unique system of magnetic fields that pull and push th train along the guideway. The electric current supplied to the coils in the guideway 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.
6 Maglev trains float on a cushion of air’ , eliminating friction. This lack of friction allows these trains to reach unprecedented ground transportation speeds of more than 500 kph, or twice as fast as the fastest conventional train. At 500 kph, you could travel from Paris to Rome in just over two hours.
詞彙：懸浮electrified v.使帶電 n. 懸浮magnetize v. 使帶磁 導向槽line v.排列成行 推進underside n.下側，下面 n.推進 undercarriage n.車盤
註釋：
1. Maglev is short for magnetic levitation :maglev 是 magnetic levitation 的 縮略詞。
2. opposite poles attract and like poles repel each other:異極相吸，同極相斥
3. AA—cell battery:5 號電池
4. at least not the kind of engine used to pull typical train cars along steel tracks:至少不是沿著軌道拉動典型的火車車廂的那種發動機。
5. the magnetic field created by the electrified coils in the guideway walls and the track combine to propel the train:由嵌入導向壁內的電磁線圈產生的磁場加 上軌道，一起推動火車前進。The magnetic field和the track是句子主語，created by the electrified coils in the guideway walls 是過去分詞短語，用作定語，修飾 the magnetic field.
練習：
1. Paragraph 3
2. Paragraph 4
3. Paragraph 5
4. Paragraph 6
A The Main Components of the Maglev Train System B High-speed Maglev due to Zero Friction C The Working Principle of the Maglev Train D Differences between Polarity and Magnetic Field E Comparison of Maglev Trains with Traditional Ones F Maglev with a Powerful Motor
5. Several countries in the world are using strong electromagnets
6. You can connect a wire to the positive and negative ends of a battery
7. A unique system of magnetic fields is created by the coils
8. The frictionless maglev train enables you A to develop a maglev train rail system
B To explain why maglev trains are faster
C to pull and push the train forward
D to create a magnetic field
E to experiment with the maglev train
F to travel from Paris to Rome in about two hours
答案與題解：
1. A第三段了舉了磁浮列車的三個組成部分，動力源、金屬線圈和此貼。選項A概括 了第三段列的內容。
2. E第四段就磁浮列車和傳統火車進行了比較：磁浮列車沒有發動機而傳統火車有發 動機。選項C用comparsion來概括是準確的。
3. C第五段比較詳細的介紹了為什麼磁浮列車會向前運動，也就揭示了磁浮列車的工作原理。
4. B在第五段解釋了磁浮列車浮起和向前運動的原理之後，作者在第六段中進行了磁 浮列車速度奇快的原因：去除了傳統火車的車輪於鐵軌的摩擦。
5. A選A的依據是本文第一段第一句：A few countries using powerful electromagnets to develop high-speed trains, called maglev trains.
6. D第二段說，把電線與乾電池相連線就能產生一個小磁場，而磁浮列車的運動原理與 此相同。第二段第四句是選擇D的依據。
7. C 第五段的第二句，即 “0nce the train is levitated， power is supplied to the coils within the guideway walls to create a unique system of magnetic fields that pull and push the train along the guideway” ，是選擇 c 的依據。
8. F本文最後一句舉出坐上時速500公里的磁浮列車從巴黎到羅馬只需約2小時這個例 子來說明磁浮列車速度之快。
譯文：磁懸浮列車
一些國家正在使用強有力的額電磁體發展高速列車，這種列車叫作磁懸浮列車。Maglev 是磁懸浮的縮略詞，它意味著這些列車漂浮在導向槽上，導向槽是使用磁鐵的基本原理來替 換原來的鋼輪子和鋼軌道的列車。
如果你曾經玩過磁鐵，你知道異極相吸，同極相斥的道理。這是電磁式推進背後的基 本原理。電磁體與其他磁鐵在吸引金屬物品方面是一樣的，但是電磁力是暫時的。你能通過 銅絲連線一節5號電池的正負極很容易地自己創造出一個小的電磁體。這就創造了一個小磁 場。如果你從電池分開導線的任意一個末端，磁場就消失。
這個導線和電池實驗創造的磁場是磁懸浮列車系統背後的簡單想法。這個系統有三個成 分：一個大電能來源、金屬卷排列成導向槽或軌道和附著在列車下面的大的導電磁體。
磁懸浮列車和傳統列車之間的一個很大的大區別是磁懸浮列車沒有發動機一一至少不 是沿著軌道拉動典型的火車車廂的那種發動機。磁懸浮列車的發動機相當不顯眼。代替礦物 燃料的使用，由嵌入導向壁內的電磁線圈產生的'磁場加上軌道，一起推動火車前進。
導向槽是沿著軌道延伸的帶磁性的線圈。它排斥在列車的車盤上的大磁鐵，允許列車在 導向槽之上1一10cm之間懸浮。一旦列車被懸浮，就把力量供給在導向槽牆體之內的線捲來 創造出一個單獨的磁場系統，沿著導向槽推拉列車。在導向槽牆體內供給線圈的電流不斷交 替改變被磁化的線卷的極性。在極性上的變化造成了列車前面的磁場向前拉動列車，而在列 車後面的磁場增加更多向前推力。
磁懸浮列車漂浮在氣墊上來減少摩擦。這種缺乏摩擦(的狀態)讓這些列車超過500kph 的速度，(這個速度)是地面交通工具史無前例的速度，或者是最快的傳統列車兩倍的速度。 500kph，你可能用剛好超過兩個小時的時間從巴黎旅行到羅馬。
