pantograph pan

例句：

1. 1.The pantograph is used to pull heavy loads across the tracks.
   拉车机用于在轨道上拉动重物。
2. 2.The tramway was built to improve transportation in the city.
   有轨电车是为了改善城市交通而建造的。
3. 3.The tramcar was a popular mode of transportation during the 19th century.
   有轨电车是19世纪流行的交通工具。