The importance of simulation calculations in developing railway vehicles and their subsystems is consistently growing compared to physical experiments and track tests

Purpose. The main purpose of the study is to compare and confirm the results of theoretical studies of locomotive motion along the straight and curved track sections in the set range of operating speeds, which is essential for determining their dynamic qualities. The conducted research complex is one of the prerequisites for improving the reliability of the rolling stock mechanics, in particular the bogie parameters. Methodology. The research was carried out by numerical integration of the dynamic loading of a railway vehicle using one of the modern software complexes. In this study we used the mathematical model of locomotive spatial oscillations obtained using Lagrangian equations of the second kind. Findings. Authors carried out theoretical research and performed the analysis of the vehicle behavior during the motion along the track section, which in the vertical plane has no geometric defects, and taking into account the inequalities on the example of the main locomotive. The researches were carried out both analytically and with the help of the modern software complex. Comparison of the graphs shows that the results obtained by different methods coincide with sufficient accuracy. Originality. Based on the results of many years of work, the authors present the General Classification of Locomotive Mechanics, which may be useful to researchers, who are involved in the assessment of the dynamic qualities of new and upgraded types of rolling stock. Practical value. A new licensed modern software complex has been applied, which makes it possible to use it in the design, modeling of units of rolling stock and their elements; during theoretical and experimental studies, comparison of their results. The results of theoretical research can be taken into account for the preliminary research during creating the reliable constructions of a new vehicle, further improvement of the mechanics, modernization of the existing units of rolling stock during field tests.

The paper is created within a project which aims to design a system of active wheelset steering for an electric four-axle locomotive. The wheelset steering system enables reduction in forces acting in the wheel-rail contacts in a curved track and consequently a reduction in wear and maintenance costs of both vehicles and rails is achieved. The project consists of three main parts: computer simulations, scaled roller rig experiments, and field tests. The paper is focused on the fundamental aspects of the first and the second part on the project. Track curvature estimation based on the rotation of the bogies towards the car body is proposed and assessed by computer simulations across varying track radiuses, vehicle speeds, and friction conditions. The scaled roller rig has been innovated in order to simulate bogie run in a curved track with uncompensated value of lateral acceleration and instrumented with a system of measurement of lateral wheel-rail forces. The experimental bogie has been equipped with systems of active wheelset steering and measurement of axle-box forces. The experiment setup, newly developed and applied systems of forces measurement and wireless signal transmission, and results of the first experiments are described in detail. Performed computer simulations and scaled roller rig experiments show that active wheelset steering is effective and practically implementable method of reducing guiding forces acting between railway vehicle wheels and rails in a curved track.