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Determination of frictional condition of the running surface and side surface of the top of rail (lubrication) that ensures the best interaction of the rolling stock wheels and the rail, reduces the force action and thus ensures the track stability and reduced side wear of rails in the curved tracks is relevant for all the rail net.The objective of research is to determine the influence of frictional condition of the track rail surfaces on the interaction forces in the “wheel/rail” contact with various motion parameters (speed, radius).The theoretical and experimental methods were used in the research. The theoretical methods include multioptional computer modelling of axial and lateral forces that appear in the curved tracks during the freight train movement in the software package “Universal Mechanism”. The modelling results were processed with the use of correlation and regression analysis. The experimental methods include full-scale measurements in the existing track and results processing.According to the research results, the theoretical algorithms for assessment of influence of the running surface lubrication on the forces. The option of frictional condition of the wheel and rail interaction surfaces has been established to ensure reduction in the operating expenses for surfacing and rail replacement, energy costs for haulage of freight train.

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A railway at all stages of its life cycle (design, construction, operation) interacts with the environment. The environment can be divided into two components, which, depending on the geographical location of the area and its economic development, are characterized by their regional factors. Natural: climate, relief, geology, hydrology, etc. Economic: the development of the area, the density of population and transport networks, industry, etc. The environment affects the choice of the main technical parameters of the railway, design characteristics, methods of construction and operation, and therefore, construction and operating costs. For the analysis of regional factors, a conditional parameter is adopted, the value of which changes in the same direction as the regional parameters. The regression equation between these parameters and the construction cost of 1 km of railway in the considered areas was revealed.

On the railway, one of the bottlenecks in increasing the speed of trains are curved sections of track. When passing such sections by the crew, a centrifugal force arises, which is proportional to the square of the speed and inversely proportional to the radius of the circular curve. This force is partially neutralized by elevation of the outer rail in the curve. There is a so-called outstanding acceleration, the magnitude of which is limited by technical conditions. On high-speed railways, when the permissible outstanding acceleration acting on the passenger is exceeded, trains with a car body tilt are operated to neutralize this acceleration. The tilt of the body can be passive due to centrifugal forces and active with the help of special tilt mechanisms. In any case, the tilt speed should be linked to the process of passing the curved section by train. It is shown that the use of the biclotoid curve design smooths the inertia of the kinetics of the car body tilt. Biclotoid design is the design of a curved section with two transition curves butt-to-butt, without a regular circular curve. Such a design reduces the forces of interaction between the wheel and the rail, increases the smoothness of the train movement, which makes it easier to adapt the process of tilting of the body to the passage of a curved section by train. It is proposed to take into account the concept of “force impulse”. This will allow, at high speeds, to use a more technically permissible outstanding acceleration equal to 0.4 m/s2.