Environmental protection is one of the most important global issues in recent years. Life cycle assessment (LCA) is now recognized as an effective tool for quantification of the environmental impact of various products in the life cycle. Although a method of LCA has not been established, LCA has already been applied to electric appliances and cars, etc. We performed fundamental investigation of LCA about Shinkansen vehicles, ties and trolley wires as a case study in the railway system. As a result, we obtained some knowledge of the application of LCA to railways.