Risk analysis of level crossing accidents based on systems control for safety

摘要

Train protection systems in Japan such as signalling systems and level crossing protection systems have been mostly developed by the improvement of individual subsystems in their performance as well as specific post-accident measures to prevent similar accidents from happening again. However, level crossing accidents are still a major contributor to the total number of railway accidents. The importance of prior risk assessment of the total railway system increases, and risk management is to be desired for taking efficient measures without any degradation of the present safety level. This paper, with consideration of accident sequences and multilayered safety functions, presents a simple feasibility study for quantitative risk assessment of level crossing accidents with the aim of efficient and effective safety management for Japanese railway systems. Accident scenarios are described which initiate from a trapped motorcar through the failure of protection systems, including human actions. A simple phenomenal model is introduced in evaluating the accident occurrence probability. The positive correlation between the train velocity and accident frequency is derived, which can be considered acceptable as common sense.