Software safety criteria and application procedure for the safety critical railway system

Software is widely used in the railway system such as train propulsion system, brake system, train control system, train detection system and driver display unit. Unfortunately, there is no software criteria and development procedure that are required to get the qualified software. Although analysis and evaluation of each step in the software lifecycle are the basic activity, direct coding to get some required functions is the main activity in the railway industry. The evaluation is just carried out in the system level functional test. Because the software has uncertainty in itself and difficulty in evaluation due to the invisibility, Sophisticated and exhausted examination is required throughout the lifecycle. The MLTM (Ministry of Land, Transport, and Maritime Affairs) in Korea is trying to improve the software development ability in the railway industry, and to ensure the quality and safety of railway software following announcement of the safety criteria for the safety critical railway software. This paper suggests safety criteria and software development process for safety critical railway system for more detail description.