Introduction. The paper considers the airflow around a railway car at different directions of its speed. The main purpose of the study is to determine the values of the longitudinal and transverse forces acting on the car for the entire possible range of changes in the angle of attack of the airflow.

Materials and methods. The simulation of airflow aerodynamics is performed in the ANSYS CFX software package, designed to perform tasks using the finite volume method. During the calculation, the Reynolds-averaged Navier–Stokes equations were numerically solved, and for their closure was used the k–ε turbulence model.

Results. The authors obtained dependences of the distribution of flow velocities and pressures on the frontal and lateral surfaces of the vehicle, as well as the values of the longitudinal and transverse forces acting on the car from the wind for different values of the angle of attack of the airf low. It is shown that the value of the angle of attack of the airflow has a significant effect on the positions of the current lines and the values of aerodynamic resistance coefficient of the car. During the calculations, it was found that the longitudinal force acting on the vehicle under consideration is maximum at the values of the angle of attack of the airflow from 10 to 30°. The greatest transverse forces are realised at angles of attack from 45 to 90°.

Discussion and conclusion. The developed method of computer simulation of streamline by airflow may be used to analyse the aerodynamic forces acting on other vehicles. The obtained results during calculations could be used in the digitalisation of production processes for the operation of railway rolling stock.

Introduction. The problems of rail durability and methods of forecasting it in conditions of increasing traffic density continue to be relevant. High stresses occur in the area of contact between the wheel and the rail, caused by the efforts of their interaction. They are considered in assessing contact strength of rails, and for their calculations effective and proven methods were developed. In addition to contact stresses rails contain residual process stresses that appear during cold straightening and thermal hardening, but these stresses undergo changes during rail operation. These stresses are not well studied. The distributions of technological residual stresses in the inner points of the rail are obtained by computational and experimental methods. Service residual stresses were studied by X-ray method mainly for rails made of foreign grades of steels with a long service life. The aim of the article is to determine the residual service stresses on the tread of P65 rail under the inf luence of long-term force action of the wheels of heavy-load cars.

Materials and methods. In order to determine the residual service stresses on the tread of rail, a 750 mm long piece of rail was used. It has been in service for 20 years in heavy traff ic transit. The deformations were measured using the electric strain gauge measuring method. Strain gauges with a base of 5 mm and a resistance of 52.4 Ohms were used for measurement. Longitudinally, 9 strain gauges were glued in parallel to the rail axis, and 4 strain gauges were glued transversely. The stress relaxation method was used to determine the residual stresses.

Results. The authors obtained distributions of longitudinal and transverse residual service stresses over the width of the tread of rail and performed their analysis.

Discussion and conclusion. The obtained values of the longitudinal and transverse residual service stresses at the points of the tread of rail are in agreement with the results obtained by other authors using X-ray methods. When examining residual stresses in rails with sufficiently long service life using X-ray methods, it was found that the greatest stresses of approximately the same value arise in a subsurface layer with a thickness of about 10 mm. In this layer, there is the greatest probability of fatigue cracks. Considering the obtained residual stresses in the methods of modeling the processes of accumulation of rolling contact fatigue damage would allow to improve them and increase the accuracy of the obtained results.

Introduction. From the experience of operating multi-axle wagons with four-axle bogies in their design, it is known that the majority of failures in operation occur on the connecting beams. The object of the study is the connecting beam of a four-axle truck of a freight car. The purpose of the study is to evaluate the effect of transverse transshipment of the car body on the service life of the connecting beam. Analysis of the work on the strength and load of connecting beams in ope ration was carried out, which shows that the main mode of damaging effects in operation, leading to the destruction of connecting beams, is the transverse transshipment of the car body.

Materials and methods. The amplitudes of dynamic stresses were estimated using the finite-element method in the ANSYS software environment. The stress amplitudes in the connecting beam were evaluated according to standardised loading modes without considering transshipment, and the stress amplitudes from the transverse transshipment of an eight-axle cistern car were separately evaluated.

Results. The fatigue strength of the connecting beam was assessed, considering the transshipment of the car body during movement. The results of comparative calculation of the service life of the connecting beam are obtained, depending on the consideration of the transverse transshipment of the car body using the example of an eight-axle cistern car.

Discussion and conclusion. The service life of the connecting beam of an eight-axle cistern car is calculated according to standardised loading modes, including and excluding the transverse transshipment of the body. The research shows that the service life of the beam, estimated without considering the transverse transshipment of the car body, does not correspond to statistical and experimental data.

Introduction. This paper discusses the validation and verif ication process of the finite element model (FEM) of the elastic clamp of the rail fastening system. Validation and verif ication are conducted to obtain clamp model that allows to sufficiently evaluate the stress-strain state of clamp condition for specified loading cases. Reliable calculation results signif icantly reduce the possibility of mismatch of stiffness and strength indicators with design characteristics.

Materials and methods. The elastic clamp CP369.102 is chosen as the clamp under study. The development of its FEM is carried out considering real geometry of the product obtained by 3D scanning and the elastic-plastic model of the material. The verification of the FEM is conducted by analysing the mesh convergence, the quality of finite elements and by comparing with the results of analytical calculation. Validation involves comparison of natural and virtual experiment results for two parameters: the stiffness of the clamp in the pressure zone on the end sections and the stresses on the lateral sections of the clamp. The strain gauge method was chosen as the method for measuring stresses is the natural experiment.

Results. The obtained results showed acceptable convergence between the natural and virtual experiments for two parameters: the stiffness of the clamp in the pressure zone on the end sections and the stresses on the lateral sections of the clamp. For the f irst parameter, the deviation between natural and virtual experiments is 4 %, for the second — from 8.3 to 15.4 %. These indicators testify to the suff icient accuracy of the developed model.

Discussion and conclusion. Possible reasons for the discrepancy of the results for the stress parameter are proposed and discussed. Further studies are planned to improve the accuracy of the developed FEM, aimed at evaluating the sensitivity of strain gauges to transverse and tangential deformations. Validation of the FEM conf irmed its suitability for use in engineering calculations for clamp design, development of clamp test methods based on it, and other scientific research.

Introduction. Modern transport systems of regional (suburban) passenger transportation face the problem of excessive route duplication between rail and road transport, which leads to irrational use of resources, increased operating costs and decrease in the quality of public services. The relevance of studying route network duplication indicators is due to the need to optimise transport infrastructure, minimise route crossings and increase the efficiency of passenger traffic flow distri bution. At the same time, route duplication is not an exclusively negative phenomenon, as in certain cases it helps to increase transport accessibility and flexibility of passenger movement.

Materials and methods. Methodology has been developed for calculating the indicators of duplication of the route network of railway and automobile transport at the passenger transportation range of the district subordination. Statistical data from Belarusian Railways on the volume and structure of passengers transported by rail by the types of communications, as well as the number of passengers sent from stations along the routes were used; data from passenger transportation operators and car carriers on routes and f lights related to the analysed range. In order to assess the dup lication of passenger transportation routes, the key indicators are the route intersection coefficient, the indicator of the competition of transportation capabilities and the eff iciency of passenger traffic distribution.

Results. Analysis of route network duplication at testing area revealed a high level of railway and road routes crossings in the Minsk — Osipovichi and Osipovichi — Grodzyanka sections. The integral duplication indicator varies from 0.01 to 1.04 and from 0.55 to 5.52, respectively, indicating a different degree of competition and complementarity between transport modes. The authors propose optimisation measures to reduce the frequency of railway routes with the redistribution of passenger traffic f low to road transport, which reduces operating costs and increases efficient allocation of resources.

Discussion and conclusion. The development of an integrated approach to calculating route network duplication at the regional level not only optimises the use of infrastructure, but also contributes to the sustainable development of transport systems, which meets the goals of increasing accessibility and efficiency of passenger transport services.

Introduction. During the war, the country’s railway institutions faced the task to reorganise their work into a mobilisation mode as soon as possible. It became clear almost immediately that in new conditions, the functioning of several narrowly focused institutes was not advisable, and therefore, at the end of 1941, all the branch institutes of the People’s Commissariat of Communication Routes of the Soviet Union were merged into the All-Union Scientific Research Institute of Railway Transport. The rapidly changing situation in the field of transportation required science not only to make operational and practical decisions, but also to take additional steps to move scientific activities to the frontline zone. In this regard, the management of the Institute decided to create a network of scientif ic correspondent points.

Materials and methods. Publications in the Railway Engineering journal for the period of 1942–1945, as well as archival materials of the Institute, were used in the article.

Results. The role of scientific correspondent points in the restoration of communication routes during the war is highlighted. It is stated that the network of scientific correspondent points has become an effective organisational form for conducting applied research in environment close to military. This step resulted in a number of studies and developments that facilitated the operation of railway transport in the emergency conditions of that time.

Discussion and conclusion. The materials of the article may be useful both for scientists and researchers studying the railway industry, as well as for industry heads. In addition, it may appeal to railway historians who seek to deepen their knowledge of the formation and development of this field.