Recently, various 4D CAD systems for visualizing construction schedule data are being developed. Specially, in case of railway project, the numerical information of progress data should be changed with visualized data by long construction section because the railway project consists of long length in construction site. This study suggests a case study of development of 4D CAD system for visualizing schedule information and the major functions of developed system are verified by railway project. The detailed application procedure of 4D CAD system including input data for a railway project is described in the study. The practical application of 4D CAD system can be improved in railway project by these demonstration researches.