Skip to Main Content
Ariane 5 rocket which is a test flight of European Space Agency was exploded 37 seconds after launch due to a malfunction in the control software. The amount of this loss is more than US$370 million. The accident has initiated the criticality of the software safety. Nowadays software is widely used in the safety critical system because of the merit of the flexibility. But the flexibility makes it difficult to predict the software failures. This paper suggests software safety criteria for the safety critical railway system and describes the quality management procedure of the railway software.