The research is aimed at developing a predictive model of the risks in railroad transport when using diagnostics of the axle boxes of freight wagons, which will allow assessing traffic safety during the operation of freight wagons. To develop a predictive model of the risks in railroad transport, the approaches of the probability theory were used. The constructed predictive model of the risks makes it possible to assess traffic safety during freight transportations; to determine further measures to reduce them; to evaluate the diagnostic method. The authors developed a predictive model of the risks in railroad transport when using the diagnostic methods of freight wagons’ axle boxes during maintenance and repair of axle box. This model includes the probability of failure-free operation of the axle boxes of freight wagons, the probability of identifying of the technical condition of the axle boxes of freight wagons, the significance of the diagnostic parameter and its relative assessment after appropriate maintenance, repair or technical control.

Purpose. The research is aimed at developing a mathematical model for determining the risks in railway transport during the diagnostics of axle boxes of freight cars, which will provide an assessment of traffic safety in the case of freight transportations. Methodology. To develop a mathematical model for determining the risks in railway transport, a continuous static model of the dependence of the level of individual approach of service personnel on the level of common interests (crew, shift) was used. Three types of dependencies were considered: optimistic, neutral, pessimistic. Findings. A mathematical model has been developed that allows assessing the risks and the level of train traffic safety during the diagnosis of axle boxes of freight cars, as well as determining further measures to reduce risks. In the process of assessing the level of individual approaches and general interests of a particular railway subdivision during maintenance and repair of the axle box of freight cars the variants for the limit possibilities of this subdivision were considered. At the same time extreme values for equilibrium distribution, for a case of dominance of maintenance and for a case of dominance of repairs of freight car’s axle box were established. Originality. For the first time, a mathematical model of risks in railway transport was developed, which is formed during the maintenance and repair of freight cars. It allows determining the level of traffic safety during freight transportations and outlining further measures to reduce risks. The method of studying the efficiency of the system of maintenance and repair of the axle box has been further developed, which, in contrast to the existing one, establishes the  dependence  of the number  of maintenance of axle boxes  on the  number of their repairs  in operation  and  will increase traffic safety. Practical value. The application of the obtained mathematical models of risks in railway transport can reduce the risks during the diagnostics of axle boxes of freight cars in order to increase the local or general level of train traffic safety.

Failures of axle boxes of freight cars due to poor-quality repair and maintenance can be reduced by applying diagnostic methods and tools. Therefore, the study carried out a study of the influence of diagnostics of axle boxes of freight cars on traffic safety of the railway transport. To reduce the magnitude of risks arising from failures of axle box units of freight cars, it is proposed to use vibration diagnostics during maintenance and repair, and to exclude the human factor, it is proposed to completely eliminate the operator’s influence on the conclusions of the diagnostic process. Also, a method for assessing the risks arising from failures of axle boxes of freight cars was developed. The presented method for assessing of traffic safety the railway transport allows you to determine and predict risks. Vibration diagnostics allows reducing the risks arising from failures of axle boxes of freight cars, thereby increasing the level of traffic safety up to 3.7 times. In this regard, it can be argued that the use of vibration diagnostics during the maintenance and repair of axle boxes of freight cars makes it possible to reduce the threats to human life and possible harmful environmental consequences on the railway transport.

Purpose. The main purpose of the study is to identify the interconnection between the risks of failure of axle boxes of freight cars and the success of performing a complex task of maintenance and repair. To do this, one should identify the sequence of calculating the values of successful completion of the complex task of maintenance and repair of freight cars, make practical calculations using the example of car repair companies of Prydniprovska Railway regional branch and identify the dependencies of failure risks of the freight cars and the process of successful completion of the task. Methodology. The paper constructs the interconnections of the probabilities of performing and not performing a complex task of maintenance and repair of freight cars. In addition, the calculation sequence of static probability estimates of successful performing and not performing of the set task, static estimates of the average deviation time and the main time of successful performing, as well as its intensity is presented. Findings. The obtained statistical data of the effective implementation of the complex task of maintenance and repair of freight cars at Prydniprovska Railway regional branch and the results of their empirical distribution throughout a period of 90 days, showed that the sample average is 24.1078 cars, the sample variance is 3.28 cars, the value of the standard deviation is 1.81 cars, and the coefficient of variation is 0.075 cars. The influence of diagnostics on the failure risks of axle boxes of freight cars during operation after fulfilling the task of maintenance and repair is also established. Originality. Based on statistical processing of experimental data, for the first time an empirical distribution of statistical data of successful completion of a complex task of maintenance and repair of freight cars was performed, which allows calculating the reliability indicators of axle boxes after maintenance and repair of freight cars. For the first time, the dependence of axle boxes diagnostics on the risk of failure of performing the task of maintenance and repair of freight cars is received, which will allow reducing the risk of failure if the task is successfully completed. Practical value. The use of diagnostics of axle boxes of freight cars during maintenance and repair can reduce the risk of failure by 2… 4.5 times.