西班牙国营铁路在1972年以前对路网干线曾做了一定数量的换轨大修和线路改造,主要繁忙干线已开始换铺 UIC 标准型54公斤/米钢轨,次要干线换铺45公斤/米钢轨,同时辅设无缝线路,RS 型混凝土轨枕,弹性扣件。从1972年起,又制定了以铁路现代化为目标的长期规划。现在,1972～1975年的四年计划已基本完成,正在进行1976～1979年新的四年计划。这两个四年计划总的目标重点是:提高铁路运 Before 1972, the Spanish state-owned railways had done a certain amount of rail overhaul and line reconstruction on the main line of the road network. The main busy trunk lines have started to swap UIC standard 54 kg / m rails and minor trunk lines for 45 kg / m rails , At the same time auxiliary seamless lines, RS-type concrete sleepers, flexible fasteners. Since 1972, a long-term plan has been formulated to modernize the railway. Now, the four-year plan from 1972 to 1975 has basically been completed and the new four-year plan from 1976 to 1979 is under way. The overall goal of these two four-year plans is to increase rail transport