The results of temperature measurements in the brake disc of a passenger car within the speed range of the emergency braking (40…120 km/h) are given in the article. The temperature measurements were made at the entrance, mid-range and exit of the disc from the brake lining in the direction of rolling. The diagrams of the temperature changes which depend upon braking time and running speed are presented. It is shown that maximum temperature values are in the area of disc exit from the brake lining during the rolling. The analytical dependences of the disc heating temperature upon the speed at the beginning of the braking operation are obtained.

The article presents the results of study of the interaction processes of a brake shoe and a wagon on the level ground and a 30 ‰ bias during braking operation. The static characteristics of the axial forces, acting upon the brake shoe, as well as their maximum values are defined. It is shown that the car-shoe intercation is characterized by a complex oscillation process of the shoe, containing both low- and high-frequency components of the change of axial effort.

Calculation algorithm for braking distances of a freight train and recalculation on cast iron brake shoes in accordance with new rules of GOST 34434-2018 "BRAKE SYSTEMS OF FREIGHT CARS. Technical requirements and calculation rules " is given. According to the above mentioned algorithms, a program was drawn up in the Excel environment, intended to complete automation of the process of computational research to determine the braking efficiency of a freight train. The program is universal, as it allows studying brake systems of different design: with one and two brake cylinders; with one-sided and two-sided application of brake shoes on wheels; with disc brake. Examples of calculation studies of the braking efficiency of the open-top car with an axial load of 25 tons are shown.

Recently, the global car building has been a tendency to actively work on the creation of innovative cargo cars that meet modern requirements. The main directions of creating innovative cars consist in increasing axial loads and speed of movement. Under these conditions, issues of strength and reliability of wagons design are becoming relevant, the ability to withstand operational loads for the entire service life. The most damaging are shock loads arising from the dissolution of cars from the sorting slodder, the production of maneuver work, when braking, the sedimentation of the train, etc. Dynamic drum tests of cargo wagons under which the longitudinal shock forces are applied to the car frame via the motor armor, to determine the dynamic stresses and their distribution in the elements of the frame and body of the wagon, the maximum permissible value of the longitudinal force at which the rim or body of the wagon may occur. Impact tests can be carried out with a single car, which hits a group of inhibited loaded wagons, standing on a direct horizontal section of the railway track, or in which the loaded car battlefield is hung at different collisions. At the same time, the establishment of the strength of the frame of the wagon with longitudinal loads at maximum stresses, with modern requirements, is insufficient. Therefore, the main task of percussion tests is to determine the carrier capacity of the carriage for the entire service life. In this regard, the purpose of percussion tests is to determine the equivalent reduced amplitude of the strain from the action of the longitudinal forces arising in operation for the entire service life of the car, which makes it possible to estimate the safety reserve coefficient. An important stage of research is the automation of testing, which allows minimizing the number of errors caused by the human factor, increase the accuracy of calculations and reduce the time for testing. Key words: longitudinal forces, scheme, algorithm, strain, amplitude, impact force.

The world trend, recently, is the creation of a high-speed cargo rolling stock for speeds with 160 km / h. In these condition, the durability of the structure of the cargo car are relevant. In the process of movement in the design of the car, voltages occur, variables in time. Under the action of alternating voltages in the design elements, the process of gradual accumulation of damage, leading to the formation of microscopic crack, and then to its development and subsequent sudden destruction - metal fatigue. One of the main properties of the wagon is the ability to withstand operational loads acting on it while maintaining this ability without destruction at all stages of the life cycle. The assessment of the bearing capacity is determined by the results of the undercarriage tests, the purpose of which is the definition and assessment of the reserve coefficient of fatigue resistance of the equivalent reduced amplitude of dy-namic stresses. As a rule, dynamic stresses are random due to the perturbing effect on the side of the rail path on the wheeled pairs, which are also random. Therefore, an important section of the study is the choice of methods for obtaining, processing and analyzing experimental data. Improving the reliability of test results is achieved by applying more advanced recording methods and processing results. To estimate the level of loading of the cargo car, methods are used based on the replacement of a real random process by some schematized process, which in terms of the accumulation of fatigue damage should be equivalent to a real process. Of the variety of schematics methods, two methods are distinguished - the method of complete cycles and the rain method, which most fully reflect the real process. The advantage of the "rain" method is the ability to process the process in real time. However, the algorithm of the "rain" method is quite complicated and does not allow processing large amounts of information. In this regard, the method of maximum discharges was proposed, which is a type of full cycles method and allows you to process an unlimited amount of information online. The schematic process is divided into classes - voltage amplitudes values. Depending on the distribution of voltage amplitudes in classes, the frequency (probability) of amplitude in the class is established. The reduced amplitude of the dynamic voltage is defined as the amount of products of the likelihood of entering each class on the average magnitude of the voltage amplitude in the class. Key words: cargo car, process, dynamic, voltage, amplitude.