随着城市化的进程,为较好地解决城市交通问题,世界各国大力发展运能大、速度快、污染少的城市轨道交通系统。地铁:即地下铁道,亦称地下铁。狭义上专指以在地下运行为主的城市铁路系统或捷运系统。但广义上,由于许多此类系统可能也会有地面化的路段存在,因此它通常涵盖了市区 With the process of urbanization, in order to solve the urban traffic problem well, all countries in the world have made great efforts to develop an urban rail transit system capable of transporting large amounts of vehicles with high speed and less pollution. Subway: the subway, also known as the subway. In narrow sense, it refers specifically to the urban rail system or the MRT system that is mainly operated underground. But broadly, since many of these systems may also have ground-based sections, it usually covers the downtown area