目前,世界各国铁路的牵引动力基本上已从蒸汽牵引过渡到电力和内燃牵引。新型牵引动力的特点是节约燃料,电气化铁路可用煤炭、原子能或水力发电,不会受能源危机的冲击。在环境保护和加强综合运输方面,铁路也有许多固有的优点和作用。因此,世界各国又出现了新建和改建铁路的热潮。缺油的国家,从石油涨价和今后相当 At present, the traction power of railroads in various countries in the world has basically shifted from steam traction to electric power and internal combustion traction. The new tractive power is characterized by fuel savings, electrified railways can be coal, atomic energy or hydroelectric power, will not be affected by the energy crisis. There are also many inherent advantages and benefits of railways in protecting the environment and enhancing integrated transport. Therefore, all over the world have seen the upsurge of newly built and rebuilt railways. Oil-starved countries, rising prices from oil and the future