The paper is devoted to a theoretical study of the car movement stability when exposed to longitudinal forces of a quasistatic nature. The authors obtained the expressions for calculating the resistance coefficient of the car lift by the longitudinal compressive force acting on the car as part of a freight train. The influence of some factor’s combination on the longitudinal forces, at which the car movement stability is still maintained, was analyzed using the analytical dependencies to assess the longitudinal loading of cars in trains. The study was carried out by analytical method for assessing the freight car stability when moving at different speeds along curved track sections. The calculations were made in a curve of small radius taking into account the inertia forces from the unbalanced acceleration. In a theoretical study, the influence of quasistatic longitudinal compressive forces depending on changes in speed and force value, as well as the influence of friction in the wheel flange and rail contact and the eccentricity of fastening the automatic coupler shank on the stability were considered. When applying the results obtained, the stability of freight rolling stock can be increased, which in turn will remove some existing restrictions on the permissible speeds and increase the technical speed of train movement. Using the described methodology for determining the lift resistance coefficient will make it possible to justify the cause of derailment, as well as to develop and put into practice technical measures to prevent the lift of carriages, thrusts and shears of the track.

To identify and predict risks in the work, a method for assessing traffic safety in railway transport is proposed. On the basis of statistics on the failure of freight cars during operation, the characteristic distribution laws for types of wear were determined. As a result, the dependences of the probability of failure-free operation of freight cars on the operating life were obtained and the centers of gravity of the areas that are used to characterize and assess the risk were determined. When designing a freight car, it is possible to establish risk values obtained on the basis of statistical data, which opens up the possibility of improving traffic safety in railway transport. In the developed method for assessing traffic safety in railway transport, the use of a graphical risk matrix is proposed. It is also proposed to combine the dependencies of the probability of failure-free operation of freight cars to calculate the total risk. This allows you to get a graphical risk matrix taking into account three types of wear of a freight car to assess traffic safety. The number of dependencies of the probability of failure-free operation of freight cars can be increased if failures are observed for other reasons.

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.

МЕТОДОЛОГИЧЕСКИЕ ОСНОВЫ ОПРЕДЕЛЕНИЯ ЭКСПЛУАТАЦИОННЫХ ХАРАКТЕРИСТИК НЕСАМОХОДНОГО ПОДВИЖНОГО СОСТАВАЦель. Научная работа предусматривает: 1) подтверждение как заявленных технических характеристик вагонов и их модификаций, так и показателей безотказной работы в течение межремонтного времени или наработки; 2) усовершенствование методологических подходов оценки эксплуатационных характеристик новой и модернизируемой техники железнодорожного транспорта на примере несамоходного подвижного состава, а именно − железнодорожных грузовых вагонов; 3) решение научно-прикладной проблемы по оценке эксплуатационных характеристик новой и модернизируемой железнодорожной техники. Методика. Рассмотрены основные методологические подходы к оценке эксплуатационных характеристик на примере несамоходного подвижного состава, а именно − железнодорожных грузовых вагонов. Проводится анализ безотказности вагона, который рассматривается как сложная механическая система, где все элементы системы соединены последовательно, при этом каждый из элементов включает m последовательно соединённых деталей. Отказ каждой расчетной части приведет к отказу вагона. Таким образом, вагон является системой без резервирования. Результаты. Усовершенствована методика оценки эксплуатационных характеристик грузовых вагонов в подконтрольной эксплуатации с учетом особенностей вагонов нового поколения. Уточнены: длительность проведения испытаний, периодичность осмотра контрольной группы вагонов, контролируемые параметры вагона, причины досрочного прекращения подконтрольной эксплуатации. Выявленные в процессе подконтрольной эксплуатации отказы разделены по их характеру. Научная новизна. Авторами предложена методика оценки эксплуатационных характеристик железнодорожной техники в опытной эксплуатации на примере грузовых вагонов нового поколения. Практическая значимость. Результаты работы позволяют оценить эксплуатационные характеристики новой и модернизируемой техники железнодорожного транспорта при проведении эксплуатационных испытаний Ключевые слова: надежность; отказ; вероятность безотказной работы; эксплуатационные испытания; подконтрольная эксплуатация; вагоны нового поколения 169

An important role in the market of transport services belongs to container transportation. Railroads, especially under the conditions of increased competition from road transport, must respond quickly to the needs of the market and the growing demand for container transportation, including interstate traffic. Demand for container transportation can vary significantly during the year, which testifies to the expediency of introducing removable equipment on universal railroad freight cars that are involved in the deliveries of containers. This paper reports the design of a removable frame structure for a universal platform that could carry two 20-ft or one 40-ft container. The proposed technical solution does not require changes in the structure of the car and changes in its model; with a decrease in the demand for container transportation, it would allow this car to be used for its main purpose. According to the current methodology, the efforts that operate on the frame during the transportation of containers have been determined. The strength of the proposed structure was estimated by a finite-element method. The maximum stresses arising in the proposed structure are 164.4 MPa; they occur in the corners of the stops attached to the stand-up staples of the platform. The resulting stress values do not exceed the allowable ones. The results of calculating the removable equipment indicate its sufficient strength. Requirements for placing cargo on the rolling stock assume a mandatory check to fit the dimensions, which confirmed that the container hosted by the frame does fit them. The proposed structure makes it possible to abandon disposable fastening parts, improve the safety of container transportation, and increase competitiveness in the container transportation market.