Safety criteria and development methodology for the safety critical railway software

The main part of the system is operated by the software. Besides the safety critical system such as railways, airplanes, and nuclear power plants is applied by the software. The software can perform more varying and highly complex functions efficiently because software can be flexibly designed and implemented. But the flexible design makes it difficult to predict the software failures. We need to show that the safety critical railway software is developed to ensure the safety. This paper is suggested safety criteria and software development methodology to enhance safety for the safety critical railway system.