This study used case studies to identify the major problems and human errors that result in railway accidents, and used these cases to suggest ways to improve railroad safety. Two representative railway accidents caused by human error (the accident at Daegu station in 2013 and the accident between Taeback and Mungok in 2014) were analyzed using a fishbone diagram that included human, management, environment, and technological factors. The case study analysis showed that railway accidents caused by human error were not due to a single error, but occurred due to a series of sequential factors, including communication problems, management issues, lack of railway associated legislation, insufficient safety education, and inappropriate safety culture. These results agreed with the previous report by Reason (1990). In the conclusion section of this study, some potential safety improvement measures for the Korean Railroad Corporation were suggested.