Economic assessment of the accidental risk of natural emergencies for train traffic

Abstract

Aim. The paper is dedicated to the evaluation of the risk of transportation accidents caused by natural emergencies affecting train traffic on a specific line. The ever-growing anthropogenic burden on the environment inevitably causes climate change that, in turn, gives rise to higher numbers of extreme weather events. The latter usually cause industrial accidents and disasters. The assessment of the factors of climate-related risk that quantitatively characterize their effect on the railway infrastructure is the starting point of calamity risk management and adaptation of human activities to the ever-changing climate. Methods. The authors propose a method of risk assessment that takes into consideration the effect of various natural emergencies that affect rolling stock in motion. The method is based on elements of the probability theory and mathematical statistics. The developed method enables the assessment of the risk of a transportation accident caused by natural emergencies specific to not only a line, but a route on a railway network. Results. For the Nevinnomysskaya – Tuapse line that includes 6 sections of the North Caucasus Railway, one of which was damaged due to abundant precipitations on October 24 and 25, 2018, the risk of transportation accident caused by the effects of three types of natural emergencies on the sociotechnical system of this line has been calculated: – flood, – hurricane with wind strength of over 22 mps, – heavy rain. The parameters of such emergencies are characterized by the following factors: – frequency as compared to other types of emergencies, – average annual number of natural emergencies, – characteristic spatial scale of the natural emergency, – characteristic duration of the natural emergency. The conditional probabilities of the effects on the railway sociotechnical system of an event that has characteristic spatial scale and duration and has caused a transportation accident involving a train were estimated based on the assumption that a train flow in space follows the normal Erlang distribution of the k-th kind. The risk of transportation accident involving up and down trains travelling along the i-th line of the j-th railway caused by a hazardous effect of a natural emergency of the m-th type is identified subject to the jointness of events. Using the discounting method, an equation was obtained for estimating the mathematical expectation of economic damage by traffic safety disturbances, which allowed estimating the economic component of the risk. Conclusions. As the result, a method is proposed for estimation of the risk of transportation accidents caused by natural emergencies, an example is provided of such risk estimation, including the economic component, for the Nevinnomysskaya – Tuapse line.