This study aims to analyze the changes in urban railway network centrality by introducing metropolitan express railways and analyzing the environmental benefits owing to the activation of public transportation. Interest in climate crises is emerging and interest in the environment and carbon emissions is increasing. Countries around the world, including Korea, are declaring a "Net Zero 2050" policy to make net greenhouse gas emissions in the atmosphere zero. This study analyzed the aspects of transportation plans and transportation demand management. The change in the centrality of the urban railway network with the introduction of the Great Train eXpress (GTX) was examined. Through urban network analysis (UNA), the urban railway network, before and after the introduction of GTX was compared. Owing to the Betweenness centrality analysis, the importance of Sindorim Station and Yeouido Station in the future networks has increased. The Straightness centrality analysis revealed that stations on the GTX-B route, among the GTX stops, had high path linearity. Based on the stations with high network centrality, the introduction of public transportation activation measures can lead to the conversion of means to public transportation and the resulting environmental benefits. The revitalization of public transportation and transformation of public transportation will help create more environmental benefits.