Train Overturning Risk Assessment And Management Under Tornadoes

Tornado is a kind of very destructive natural meteorological disaster,which causes heavy casualties and losses to people’s life and property.In recent years,with the increase in the number and speed of trains and the expansion of the railway network,the danger of tornadoes attacking trains has been increasing year by year.At present,the research on the train under tornado is still in the exploratory stage,which is worth further exploration.Based on Monte Carlo simulation,this paper establishes a new analysis method of train overturning probability under tornadoes.The method is based on the existing meteorological data,the statistical analysis shows that the location,time,direction of the tornadoes are uniformly distributed;the annual occurrence number obeys the negative binomial distribution;intensity and path length are subject to Weibull distribution.The mathematical model of tornado is obtained by sampling on the basis of probability distribution.Combined with the train schedule and the railway line position,the space position distance is obtained by the time relationship between them.At the same time,according to the wind speed and direction of the train obtained from the tornado wind field model,the wind load of the train can be calculated.Finally,the corresponding wind load is applied to the overturned model of the train,and the pressure of the windward and leeward wheels on the track is calculated,and the overturned train is judged according to wheel unloading ratio.After many times of simulation sampling,the overturned probability of the train under the tornado is calculated by the ratio of the overturned number to the simulated number.Using the above methods,this paper first carries out a single railway risk assessment for the Tokaido Shinkansen in Japan.Using Japan’s tornado data from 1961 to 2015,the simulation calculated the probability of trains crossing the railway and overturning.The most dangerous stations on the Tokaido line were found by analyzing the proportions of different trains and tornadoes with different intensity when they overturned.According to the relationship between the probability of overturning and the number of trains,a method of ‘off-peak departure’ is proposed to reduce the risk.After that,this article will further model and analyze multiple railways in Texas,USA.Based on tornadoes simulated by data from 1950 to 2018 in the United States,a risk assessment of the railway network was carried out.Comparing the overturning risks of different railways per unit length,it is found that the railway from San Antonio to Texarkana is the most dangerous.According to the relationship between the distance of the train overturning and the maximum wind speed of the tornado,monitoring points can be set at different distances according to the wind speed distribution of tornadoes in different regions to improve the early warning efficiency.The evaluation method of train overturn probability proposed in this paper is based on real tornado data and railway information,which can be used as a reference for railway companies to formulate risk management strategies.