Proposal of coexistence technology of safety, reliability and flexibility in safety related real-time system and practical use to railway signalling system

Recently amount of construction about railway signalling system is steadily increasing to improve the transport services for the customer. But, at present efficiency of signal construction is very low. For example it is caused by that the period for the construction is limited to very short time at midnight or flexibility of the signalling system is low from its system architecture. To solve this problem we are now grappling the innovation of the railway signalling system. In this paper, coexistence technology of safety, reliability and flexibility in safety related real-time system and safety evaluation in practical system is discussed.