This paper illustrates some examples of socio-economic changes brought about by railroads in Korea. The Korean railroad network has been running for 110 years since it started operation in 1899. The opening of railroad system in Korea has had a huge influence on its society, not only transportation but also in the development of infrastructure and formation of new cities, such as Daejeon Metropolitan City, which were built along with the rail network. This paper will examine some examples of the influence that railroads have had on Korean society: the changes of transport route from road to railroad, the emergence of new cities, industries and culture. Also, this paper will look over the various functions of railroads in Korea, and then it compares with those of foreign countries. It gives us chance to examine a specificity as well as universality in the function of railroads.