Introduction. The authors study the section of the shuttle-service trains. Based on a detailed description and characterisation of the site, it is categorised as a man-machine and difficult-to-formalise system. It is not possible to study stability of such transport facilities using known criteria and methods. This study aimed at developing a new approach for assessing sustainability of a shuttle-service train system, taking account of its specific features and characteristics.

Materials and methods. The paper proposes the use of a neural network approach to assess the sustainability of shuttle-service trains. The input data used is a time series of freight flow on a section of the shuttle-service trains, which is the main operational indicator of the system under study. The method of artificial neural networks is chosen for modelling because it is a simple and effective tool for studying the system in question, with the values of the freight flow having a random character.

Results. An approach based on the power of neural networks is described. This indicator enables to assess quality of the model by reflecting the consistency of model results with actual data.

Discussion and conclusion. The approach presented may be used to assess the sustainability of a shuttle-service train system.

Introduction. The increase in freight traffic density and axial loads on the Eastern polygon is affecting the condition of the railway and reducing the time available for maintenance. The increased workload caused by track deformation in difficult operating conditions makes the planning and organisation of railway maintenance work much more difficult. One of the main factors affecting the safety and smooth running of trains is the geometry of the rail track, which is kept in a normal condition by track maintenance. The study examines the problem of increasing the efficiency of maintaining rail track geometry.

Materials and methods. Mathematical modelling and statistical methods were used to solve the problem. A process organisation model was created based on formalising the process of incoming and outgoing work. The estimated workload required to rectify the identified deviations was determined on the basis of the results of the track condition assessment using track measuring devices, taking into account the regulatory time standards for their rectification.

Results. The mathematical model for the process organisation of rail track geometry maintenance is presented, which allows to determine the necessary level of daily workload on a linear section to perform the full scope of works within the regulated terms, which would reduce the desicion time during the planning of works.

Discussion and conclusion. The use of this model makes it possible to simplify the planning and organisation of work on a section of track, which is particularly important at a high level of urgent and high-priority work on particularly heavy-traffic sections. Further research would focus on the development of a mathematical model, the development of a software product and its implementation into a unified enterprise automated infrastructure management system.

Introduction. The authors present the results of an experimental study of the thermal insulation properties of vacuum panels using a digital copy of the test bench. The subject of the study is a vacuum insulation panel in the form of a sealed parallelepiped with internal stiffeners. When the air pressure inside the body is reduced, the specific thermal resistance of such vacuum insulation panels becomes higher than that of modern insulation materials. The use of such panels as thermal insulation for land means of transport, particularly passenger carriages and refrigerator wagons, significantly reduces energy costs for heating or air conditioning the interior. Experimental determination of the thermal properties of vacuum insulation panels is time consuming and requires expensive equipment due to their considerable heterogeneity. The aim of the study is to develop a method for determining the thermal resistance of insulating materials with internal heterogeneity in the shortest possible time with acceptable accuracy.

Materials and methods. The research methods combine physical experiments on three vacuum insulation panel prototypes and numerical experiments on 3D models of these samples. Specifically, the test stand was calibrated using its digital counterpart — a virtual test bench created as a 3D model using SolidWorks software.

Results. The study of the transient thermal process on the stand model in SolidWorks Simulation allowed us to reduce the time of the physical experiment to 40 minutes and to determine the values of the effective thermal conductivity coefficient of the three vacuum insulation panel prototypes.

Discussion and conclusion. The study of the steady-state thermal process of 3D models of vacuum insulation panel prototypes in SolidWorks Simulation showed that the discrepancy between the experimental and calculated values of the effective thermal conductivity coefficient is less than 5%. The proposed method for determining the effective thermal conductivity coefficient of materials is suitable for use in the incoming and outgoing inspection of car insulation during overhaul.

Introduction. Measurements of forces in couplings on electric trains of different categories and types (including different types of drawbars) showed that the level of forces in couplings on suburban electric trains is higher than on urban express trains, despite the lower number of starts and stops and the presence of buffers on suburban electric trains to absorb some of the longitudinal forces. In addition, a higher frequency (statistical probability) of occurrence of these forces was observed in suburban electric trains, which determines a higher load on automatic couplers in suburban electric trains with an automatic coupler installed in accordance with GOST 3475-81 than in ES2G city electric trains, where the cushions are combined with the coupling body. The main objective of the study was to determine the load on the couplers of electric trains of different categories and types, as well as to determine the parameters of the cushions of the couplers that have the greatest influence on their load.

Materials and methods. The research methods include experimental measurement of longitudinal forces in inter-car couplings of electric trains under operating conditions with statistical processing of the results, and analysis of the effect of cushions indicators on the longitudinal dynamics of the train.

Results. The authors analyse the effect of the initial tightening force on the changes in the level of acting forces and the loading of drawbars during electric train operation. The most significant effect of this force is found to be on the longitudinal dynamics of the train and on the load on the couplings.

Discussion and conclusion. Reducing the initial tightening force has a positive effect on the longitudinal dynamics of railcars, according to the results of tests measuring the force levels in couplings. The results obtained would form the basis for further research under varying conditions and for conducting train tests.

Introduction. The authors describe the practice of checking newly built cars to assess their durability, taking into account the ultimate operating loads and their application schemes stipulated in the regulatory documents. Axisymmetric loads are not part of the bogie frame static strength assessment rules. For mechanical safety reasons, the presence of residual frame deformation asymmetry is not permitted. All-welded bogie frames are particularly prone to axisymmetric loads. It confirms the need for refinement of design methods to ensure reliability and safety of cars in service.

Materials and methods. Methods of computational analysis and computer modelling were used to determine the loading scheme and the magnitude of the axisymmetric load; experimental work was carried out on a passenger carriage with two-axle bogies and an all-welded frame in which the side beams are rigidly connected by cross beams.

Results. An additional type of derailment is justified, which is relevant for the operation of wagons with all-welded bogie frames. The load pattern of the bogie frame and the magnitudes of the load applied to the frame for the mode of operation in which the static strength of the frame is to be assessed are determined.

Discussion and conclusions. In the event of a wheel derailment, the all-welded bogie frame is subjected to maximum axisymmetric loads, which could lead to axisymmetric deformation and frame failure. The all-welded bogie frame should be assessed for static strength in derailment mode. The overload coefficients are justified. The reliability of the bogie frame in service and the safety of the traffic could be improved by developing, calculating and evaluating the design with the additional mode mentioned above.

Introduction. This article examines the current approach to the design of rotating electrical machines. An overview is given of existing software packages for modelling electromagnetic and thermal processes using numerical finite element methods, designed to replace concentrated parameter analysis of electrical equivalent circuits. It describes how modern Russian researchers solve a wide range of problems, from studying traction performance, to analysing electromagnetic disturbances, noise and vibration, to modelling and diagnosing faults. The aim of the study is to investigate the features of a modern software package suitable for modelling and visualising the magnetic field in the induction traction motor DTA-1200A of the electric locomotive EP20.

Materials and methods. The study applies a numerical finite element calculation method using an application software package that synthesises a two-dimensional computer model of the traction motor to calculate the magnetic field and formalises the calculation of output parameters based on data from technical literature, test results and reference materials. Results. One of the existing software packages is successfully piloted as a result of the study. The steps involved in the geometric construction of a traction motor cross section, the principles of setting and measuring physical phenomena, and the capabilities of the software are reviewed. The modelling characteristics of asynchronous electric motors are described. The practical application of magnetic field modelling results to estimate magnetic flux, flux linkage and power loss in a traction motor is studied. After synthesis of the computer model and calculations, the results of the finite element computer modelling are correlated with theoretical design and experimental test data.

Discussion and conclusion. The results of the study are expected to be useful to electrical machine designers and researchers involved in computer modelling of induction electric machines. On the basis of the computer model presented and verified, research could be carried out to improve the performance of traction motors, to improve and optimise their design and to create digital twins of electric machines.

Introduction. Solving a wide range of problems to maintain the strength of train undercarriage under the impact of ballast particles, such as ice chunks, during the cold season is considered a topical issue for high-speed railways. Solid objects are lifted off the track surface as a result of aerodynamic interaction with the turbulent airflow of a high-speed train. This causes mechanical damage to the bogie and its components, which could be significant and endanger road safety. The aim of this study is to assess the probability of significant damage to the traction gearbox housing from foreign objects on the way and to develop a method of protection.

Materials and methods. Housing failure potential is calculated using numerical simulation in MSC.Nastran_SOL700 environment, allowing analysis of short duration dynamic events with severe geometry and material non-linearity. The method of assessment of the structural strength of a traction gearbox housing under the dynamic action of a foreign object is described.

Results. The calculation methodology is tested on a simplified traction gearbox housing model. The methodology is then applied to models that are close to the real traction gearbox housing. The General model and the Cowper — Simonds model, which incorporates the strain rate dependence of the dynamic deformation of the material, are considered for specifying the material properties. The effect of foreign objects of different masses and relative speed on the probability of damage to the traction gearbox walls at different thicknesses is assessed.

Discussion and conclusion. Calculations confirm the probability of destruction of housings of traction gearboxes of high-speed and high-speed electric trains under the dynamic impact on the body of third-party objects. Structural solutions for protecting housings of traction gearboxes of high-speed trains from the effects of foreign objects are analysed and the most rational option is chosen. This article was written based on the authors' paper presented at the XXII Russian MSC Software Conference (HxGN Live Design & Engineering Russia 2021), November 16-19, 2021.

Introduction. The authors analyse the influence of the design features of crossings with a solid core unit with wing rails and welded rail ends (monoblock crossing) on the occurrence of hazardous failures associated with design flaws. Stress distribution to ensure uniform stiffness and avoid dangerous failures while ensuring product manufacturability is an important issue in cross design. This is achieved by rationalising the casting's longitudinal force element.

Materials and methods. A computer simulation using ANSYS finite element analysis is used to determine the influence of the location of the force element in a monoblock crossing design on the fatigue safety factor. Operational tests of the prototype crossings were carried out on the second main track of the Experimental Loop of Railway Research Institute and at the Isilkul station of the West Siberian Railway.

Results. The influence of the geometry of the longitudinal rib of the crossing and its location on the failure-free operation of the structure is studied. Based on the calculation results and confirmed tests, the final geometric dimensions of the one- piece core unit with wing rails are proposed, taking into account product manufacturability. Recommendations are given for the positioning of the longitudinal ribs of the monoblock crossings during the design phase. The proposed design of the monoblock crossings is adopted for series production.

Discussion and conclusion. The lowest equivalent stresses are found in one of the monoblock crossing designs with two longitudinal stiffening ribs presented in the article. This design allows the product to operate in a way that prevents dangerous failures. The implementation of the principles of mathematical modelling used in this work, taking into account the adopted calculation scheme, ensures a significant reduction in the time required for the design and manufacture of crossings with a solid core unit with wing rails and welded rail ends.