Problem of ensuring motion safety of empty freight cars is most acute in relation to cars on bogies of model 18-100, which is mainly due to operational wear of wheelsets, side frames and bolsters, as well as spring suspension elements. A potential threat to traffic safety arises when a train, composed of mostly empty and lightly loaded cars, moves along track sections that have deviations in the geometry of rail track of III and higher degrees or combinations and sequences of deviations of II degree. The article presents the main results of complex studies: mathematical modeling of the dynamic interaction of the track and empty freight cars of various types of bogie wear based on the Universal Mechanism software and field tests of cars on measuring sections of tangent, easement and circular curves with a radius of 350, 650, 800, 1000 and 2050 m on the section Belorechenskaya — Maykop of the North Caucasian railway. Dynamic qualities and motion stability of empty freight cars of various types are investigated depending on the parameters of the technical condition of the running gears and the deviations of the geometry of the rail track of II and III degrees of various types and combinations when moving in tangent and curved track sections. Authors provide tables and graphs of the dependences of indicators of dynamic qualities and motion stability of universal empty freight cars of various types on the motion speed in tangent sections of the track and circular curves of various radii and easement curves containing artificial deviations of the geometry of the rail track, most negatively affecting traffic safety. Recommendations are given for correcting the regulatory documents of the Russian Railways, which regulate the permissible speed of motion of empty freight cars, depending on the technical condition of the running gear.

Investigations of the frequency of bending vibrations of the car bodies of 61-4440 model range, which includes compartment cars, staff cars, non-compartment cars, coach cars, restaurant cars and others, are described. The bodies of all cars of this model range have the same overall dimensions and are made of corrosionresistant steels (stainless) with flat corrugated sheathing of the lower (under the window) belt.

To assess the influence of the design features of stainless steel bodies on its bending stiffness and the parameters of bending vibrations in the vertical plane, a computational and experimental complex of works was carried out.

After analyzing the calculation results and experimental data, proposals were developed and implemented to increase the bending stiffness of the metal body structure with stainless steel skin. To check the implemented proposals, complex tests were carried out to determine the parameters of bending vibrations of the metal structure of the experimental body. The tests were carried out according to the combined method developed by the authors. For this, a vibrator, installed in the console parts of the body, and impulse excitation were used.

The results of testing the metal structure of the experimental body in comparison with the results of testing the car bodies of 61-4440 model range showed the effectiveness of the implemented proposals, namely: increasing the frequency of the first tone of bending vibrations by 18 %; decrease in the amplitude of vertical vibrations of the body structure at the frequency of the first tone from 12 to 50 %; decrease in the amplitude of the vertical accelerations of the metal structure of the body during oscillations at the frequency of the first tone approximately by 2 times; significant reduction in horizontal acceleration in the area of the middle section walls. The effectiveness of the implemented proposals for increasing the bending stiffness of the metal structure of the experimental body allows recommending them for the entire model range of 61-4440 cars.

The article describes a new bench for testing the reliability of passenger car windows and doors. The bench can be used in various industries, mainly in transport engineering, as well as in the construction industry. This bench is functionally designed to test the entire product (windows or doors), as well as to determine the service life of individual mechanisms of this product. In contrast to the known analogs, the new bench for testing the reliability of windows and doors allows testing under the influence of variable aerodynamic pressure arising from the operation of windows and doors on moving objects, for example on high-speed transport. Specially developed test method is proposed on this bench, which allows simulating alternating aerodynamic effects on windows and doors that occur when a train passes tunnels or when trains in opposite directions diverge at high speeds. Thanks to this, bench tests can serve as an actual addition to the existing methods of testing windows and doors of modern high-speed rolling stock.

Fourth industrial revolution covers all areas of human economic activity, including areas related to the design and operation of various products (nuclear power plant building, freight car, MEMS devices, etc.) throughout their entire life cycle. One of the main tools for digital transformation of industry to meet new competitive requirements is the Digital Twin, which is always built for a specific physical object. The introduction of digital twins technology into the life cycle of a freight car will increase economic efficiency throughout its life cycle.

Effective use of the digital twin technology is possible only when an adequate virtual model of the space surrounding this physical object is created. In this regard, predicting the behavior of a structure during motion on the basis of a high-precision model of a digital twin of a physical object requires the creation of a virtual space in which a virtual operation area will be implemented, which provides the possibility of mathematical modeling of motion. To do this, it is necessary to create virtual stands and operation areas, where it will be possible to carry out numerical tests. Creation of a high-quality virtual space will drastically reduce the number of field tests carried out, and study the effect of a larger number of parameters on the performance characteristics of a physical object.

Creation and use of digital twins is consistent with the goals, objectives and action plan of the Strategy for the development of transport engineering in the Russian Federation for the period up to 2030. The introduction of digital twins in railway transport, in particular in freight rolling stock, will make it possible to correctly assign the service life, overhaul times, and increase operational efficiency, collect information about the real load, etc. To maintain competitive advantages over other modes of transport, the transport industry needs to develop towards the introduction of elements of the fourth industrial revolution, including digital twins.

An approach to the selection of locations for compact container sites at railway stations of main railway lines for carrying out freight operations with transit container trains is described on the example of an investment project of the JSC “Russian Railways” for organizing transportation by “Cold Express” trains. To ensure the possibility of organizing the motion of container freight trains with its reception at the station directly to the loading and unloading front, certain conditions listed in the article must be met. The approach is based on the principle of minimizing costs and maintaining the operational parameters of the reconstructed railway stations while implementing the principles of container logistics. It was concluded that the reference railway station for placing on it a container terminal specializing in handling container transport trains (including “Cold Express” trains) should be a station that has a little-used electrified receiving-departure track with a length of at least 1050 m, for which there is the possibility of receiving and departure trains in all directions and near which there is an open freight area with a hard surface with the possibility of approaching trucks. Also, conditions for the unimpeded operation of loading equipment should be ensured, i. e. there should be no obstacles in the form of pedestrian bridges and overhead catenary supports. On the pilot route Vladivostok—Moscow—St. Petersburg, 18 stations were selected, located in large cities or tend towards large cities. The analysis showed that in real conditions there are no stations that fully meet these criteria, from which it was concluded that it was necessary to carry out capital-intensive measures of various volumes associated with the achievement of the necessary parameters of the stations, such as electrification or lengthening of the track, reconstruction of the station necks, arrangement of the site, car entrances, as well as other measures.

Introduction of a new transport product in urban agglomerations helps to attract additional passenger traffic by changing parameters of organizing the operation of suburban trains. Problem of determining the effective parameters of the route network of suburban-urban railway communication in order to achieve acceptable financial results for the owners of infrastructure and carriers is considered. Controlled variables are determined that characterize the route network of suburban-urban traffic and include the type of train schedule, the operation interval, the routes, the traffic volume of suburban-urban trains, the station of departure and arrival, the service class. It was also determined that the distribution of passenger traffic correspondence over the network of transport products depends both on a set of controllable variables and on the time of travel by rail when using a transport product, taking into account the execution of terminal operations at points of departure, destination, transfers, waiting for trains, and travel on trains. The objective function for the carrier and the owner of the infrastructure, which is identical for both participants of transportation, is considered, while the components of investment costs and direct production costs for transportation activities and income receipts that ensure the break-even of this activity are different for each participant in transport services. Relevant constraints for the task, due to the resources of the railway infrastructure and rolling stock, have been determined. Authors provides the principles of solving this multicriteria problem by finding a group of the best options by a directed enumeration of alternatives with the subsequent selection of the resulting solution by the methods of compromise control. The research results are intended for use in projects for the development of suburban-urban traffic in large urban agglomerations.

Adoption by Russia of the Kigali Amendment to the Montreal Protocol on substances that deplete the ozone layer posed a very difficult task for consumers of artificial cold, including rail transport, to find an acceptable alternative to the R134a freon and mixtures based on it, which is being phased out. Considering that there are no equivalent alternatives to these substances on the market, it was proposed to consider the use of widely known and previously used working fluids in climate technology, based on the positive experience of the European Union (EU) countries. The article analyzes the reasons for the bans on the use of hydrofluorocarbons, presents the mechanism for the legal use of refrigerants that are safe for humans and nature in the EU and a version of the roadmap for converting the climatic units of the Russian Railways holding to R22 freon and other types of fluorocarbons within the framework of the Kigali Amendment.