the traditional metro system is droved by rotating induction motor, and the power is transferred to the wheels and axles through the corresponding mechanical gearing equipment, and its force of traction or brake, which is formed through the function of wriggling between the wheel and track, drives or stops the vehicles 由于它具有许多普通电机所不具备的优点,因而被广泛应用于许多场合。随着世界城市化发展进程的加快,公共交通运输的压力越来越大,在这种形势下,直线电机驱动的城市轨道交通系统显示出其独有的优势。