METHODOLOGICAL ASPECTS OF THE FORMATION OF QUANTITATIVE ASSESSMENTS OF SAFETY OF AUTOMATED RAIL TRANSPORT CONTROL SYSTEMS USING RISK MANAGEMENT APPROACHES

The article examines the issues of  improving the methodology for  identification and assessment of the  limits of existing risks of technical  operation and maintenance of  automated railway transport control systems, determining and classifying the level of severity of the  consequences of failures for the further selection of appropriate risk management methods that will be applied in the development of  innovative control systems of railway infrastructure transport. To resolve the issue, it is proposed to consider the effects of external factors and means of the system itself, which are designed to reduce risk in order to comply with a given level of functional  safety using a risk-oriented approach. The main functions of risk are defined: protective, analytical, innovative,  regulatory. The risk management process is based on the results of risk identification and assessment in order to reduce the consequences of dangerous factors and threats, based on the results of which a structural block diagram of the process was built using the principle "as low as reasonably achievable"  (ALARP). 9 stages of risk management are defined:  - risk assessment of potential  consequences; - decision-making regarding risk and its acceptability; - development of measures to  eliminate risks or reduce them to the lowest acceptable level; - determination of risk probabilities and completion of the table of risk probabilities - categories of the probability of occurrence of dangerous factors or threats; - assessment of the severity of their consequences and completion of the risk severity table with the definition of the severity category of the consequences of dangerous factors;  - determination and classification of  the level of severity of the  consequences of train traffic control system failures; - assessment of risk acceptability using the risk assessment matrix and determination of risk acceptability indices; - risk assessment and decision-making regarding the acceptability or  unacceptability of risks. - making a decision about the need to control the assessed risk. According to the results of the study, taking into account simplifications and assumptions, it was determined that the most vulnerable elements of the control system and timely and high-quality maintenance require identification and assessment of risks. That is, using statistical data on the failure of technical equipment on the one hand and statistical data on their technical maintenance, it is possible to calculate and assess risk levels and determine and classify the level of severity of the consequences of failures and the degree of their acceptability using quantitative and qualitative methods. The obtained results will be applied to the selection of appropriate risk  management methods and further improvement of automated  management systems by expanding their capabilities and providing them with additional functions.