India, the Republic of India is a country of one of the world’s oldest civilizations, the largest state in the world by population — 1.42 billion people (end of 2022), occupying an area of over 3 million square kilometers. India, which has accelerated the pace of its socio-economic development in recent decades, is playing an increasingly important role in the international arena every year, including as one of the BRICS organizers. The state railways of India are managed by the Ministry of Railways of India represented by Indian Railways (99 % of the country’s railway network) and are, despite the dominance of motor transport, remain one of the main modes of transport. During the year, the railways of India transport more than 8 billion passengers (2^nd place in the world after Japan), the staff of the railways of India will amount to 1.2 million people (the 7th employer in the world). Railway transport in India is developing intensively, in recent years, work has been intensified on the organization of high–speed traffi c on a number of lines of existing railways, the fi rst high-speed railway line Mumbai — Ahmedabad is being built with a normal gauge of 1435 mm with a length of 508 km, designed for a maximum train speed of 350 km/h. The authors of the article have repeatedly visited India, visited various railway enterprises, railway educational institutions — universities and institutes, met with industry leaders at the Ministry of Railways of India, traveled along the country’s railways along a number of routes with a total length of about six thousand km.

   Transport is a major water consumer and source of environmental pollution, including water resources. In order to preserve and improve water quality in water bodies at industrial and transport enterprises, including railway enterprises, water protection measures entailing permanent signifi cant funding are required.

   The study is aimed to develop a methodology for determining dependence of water quality of the water body on the real financing of water protection measures; theoretical justifi cation of the choice of water quality of the water body from the quality of wastewater (WW) of water users, discharging them into the water body and amount of financing of water protection measures.

   The solution of the task of determining the best water quality in a water body under limited fi nancing of water protection measures and rational distribution of fi nancial resources between water users, including transport infrastructure objects, is proposed. Financing of water protection measures in Russia is less than abroad and has been decreasing over the last three decades. The limits for pollutant concentrations in pollutant discharges into water bodies and water disposal systems in Russia are often set very strict, sometimes more stringent than those for drinking water, which leads to unjustifi ed spending of investment costs. It is pointed out that at present in Russia market relations in the field of nature and, in particular, water use have not been formed. The basic diffi culties at realization of these relations in our country are designated. When using the proposed methodology, the rational quality of water resources of water users by limiting pollutants and the rational distribution of funds for water protection measures among water users within the limited amount of financing are determined. The extent to which water quality in a water body changes is also determined. The possibility of practical application of the proposed methodology is considered.

   On the basis of recent research, a review has been carried out on the experimental determination of the mechanical parameters of the materials used as ballast material. Considerable attention is given to the well-founded selection of input data for the calculation, i. e. quantitative characteristics of the elastic properties of the materials used to form the ballast layer, which is treated as a continuous medium. It appears that this approach makes it possible to assess correctly the influence of grain (grain size distribution) distribution, ballast layer thickness and material type on the stability of a railway track to vertical and horizontal disturbances. The data of this review show that material properties and particle size have a signifi cant impact on elastic moduli and in finite-element modelling of static strength problems, grain-size distribution and material properties are only taken into account through these moduli. Experimental results show a non-linear dependence of the elastic moduli on the stress behaviour of the ballast prism, which is related to a densifi cation of the medium in compression. However, it is established that, after a suffi ciently large number of loading cycles, the medium can be treated as linearly elastic. In general, the results of the research allow establishing requirements for damping, geometric and granulometric parameters of the ballast prism.

   There are many factors that infl uence the process of organising train movements, quality radio communication being one of the most important. The intelligibility of the dispatcher’s commands to the driver is important in deciding what action to take, and in informing the dispatcher of the train situation on a particular section of the track. Sources of radio interference that have an interfering effect on the quality of the train radio signal are natural and artifi cial interference. The sources are mainly low-frequency interference. One of the constant sources of high-frequency emissions that affect stable operation of train radio communications refers to discharges generated in the high-voltage insulation of power lines, including discharges generated in the insulation of overhead wires. Spark discharges, the source of radio interference, occur both on the surface of the insulator (usually called surface partial discharges (SPD)) and inside the insulation (such discharges are called partial discharges (PD)). In the operation of high voltage insulation, those insulators that contain PD and PPD are called defective insulators. PD and PD diagnostics are carried out twice a year by means of a laboratory car. Discharge registration is performed in the visible and ultraviolet range. There are acoustic methods for registering PD and SPD. It is proposed to register discharges in the electromagnetic frequency range. For prompt detection radio interference, it is recommended to place antennas on the laboratory car, and combine measurements with current diagnostics of high-voltage insulation, that will allow increasing reliability of the results received in the course of diagnostics. To increase the accuracy of radio interference source detection, two antennas are considered to be placed on the laboratory car.

   Improvements in locomotive wheel-motor unit (WMU) design over the last decade have been made in terms of the transition to rolling motor-axle bearings (MAB) instead of plain bearings, which was the basis for the proposed study.

   The study is aimed to provide a theoretical estimation of power losses in different types of locomotive WMU MAB and its validation depending on heating temperature and bearing specifications.

   The study is aimed to determine power losses in MABs using new approaches to their determination.

   New methods of determining the power losses in the plain and rolling MABs of locomotive WMUs are suggested. These methods allow calculating the values of power losses depending on the specifications of MAB and its heating temperature. Depending on the bearing heating temperature, recommendations are provided with regard to operating conditions of a particular type of locomotive WMU bearing. It is recommended to operate motor-axle plain bearings in the temperature range of 10 to 20 °C, and rolling bearings from 20 °C and above. The suggested methodologies for calculating power losses of locomotive WMU MABs can be used to determine the energy efficiency of a given drive type, taking into account the type of the grease, its temperature, design features and operating conditions. The obtained results can serve as recommendations for the selection of the type of MAB.

   The effect of aerodynamic factors on the rolling stock and railway infrastructure has been analysed. The formation of air mass structure in tunnel structures during the movement of high-speed rolling stock has been investigated. The processes of aeroelastic interaction of rolling stock with tunnel portal structures are analysed by means of numerical simulation. The description of mathematical models and the ways of their three-dimensional realization in the Solid Works Flow Simulation software complex are presented. Methods of finite elements and volumes for the solution of the set tasks are used. The results of the numerical research of velocity fields near the tunnel portal area obtained with the help of the developed mathematical models for the cases of entry and exit of the rolling-stock into the tunnel are given. The complex structure of air masses formation in the gap between the train body and tunnel lining which leads to increased resistance to the train movement in the tunnel is revealed. The patterns in the changes of pressure dynamics on the surface of the head fairing when the train enters the tunnel are found. The fact of negative effect of high and low pressure zones, as well as their abrupt difference, on the locomotive crew and passengers has been established.

   The article examines the importance of transport for the Federal Democratic Republic of Ethiopia, and also characterizes the existing state of the main types of land transport: road and rail. The article defines the territorial location of the industrial parks of Ethiopia, on the basis of which possible directions of multimodal transport corridors, existing, under construction and promising railway and road transport facilities are assigned. The external and internal factors influencing the formation of variants of the multimodal transport network scheme based on the methodology of designing the
integrated development of a multimodal transport network are determined. This will be used to develop the scheme of the multimodal transport network of Ethiopia. The scheme will become the basis for the formation of a variety of possible strategies for gradually changing the appearance and capacity of multimodal transport network facilities and calculating options for the required freight and passenger flows along multimodal transport corridors.