西部地区的发展蕴含着巨大潜力，但也存在着许多不利因素，突出一点就是基础设施落后。西部地区深处内陆，地形复杂，交通不便，对外经济交流受到影响。不解决这一问题，西部开发中的很多政策效用将无法发挥出来。西部地区基础设施落后主要表现在交通设施不完善。铁路密度仅为? The development of the western region contains tremendous potential, but there are also many unfavorable factors. The one outstanding point is that the infrastructure is backward. Inland areas deep inland, complex terrain, traffic inconvenience, foreign economic exchanges affected. If we do not solve this problem, many policy effectiveness in the development of the western region will not be able to be realized. The backward infrastructure in the western region is mainly manifested in the imperfect transportation facilities. Railway density is only?