ОСОБЛИВОСТІ КРИТЕРІЇВ ГАЛЬМІВНОЇ ЕФЕКТИВНОСТІ ВАНТАЖНИХ ВАГОНІВ ВІДПОВІДНО ДО ВИМОГ ГОСТ 34434

Abstract

The paper deals with the analysis of the braking efficiency criteria for freight trains formed with wagons that have increased axle load up to 294.3 kN (30 ts) when moving at speeds up to 120 km/h inclusive. Increasing the efficiency of freight trains by increasing the technical and economic performance of cars by increasing the axial load to 294.3 kN (30 ts) and train speeds up to 160 km/h led to the development of technical requirements and rules for braking systems set out in HOST 34434-18. According to the new rules and requirements, the following are accepted as criteria for the braking efficiency of freight wagons, that is, up to the maximum values of the braking distances of the freight train on the site in the specified intervals of speeds of axial loads; calculated coefficients of force of pressing of composite blocks on wheels at braking; the pressing force of the composite pads on the axis in terms of cast iron pads. The calculation of the maximum allowable value of the braking distance of the freight train is performed based on the actual pressing forces and the actual friction coefficients. The paper shows that the specific braking forces obtained using the actual pressing forces exceed the calculated specific braking forces using the calculated coefficients. Based on the above-mentioned, it is concluded that the braking efficiency criteria with reference to the maximum allowable values of the braking distances and the calculated coefficients of the pressing force have a significant discrepancy between each other. It is proposed to use the actual pressure force coefficients instead of the calculated coefficients to assess the braking efficiency of the freight train. The paper presents the permissible values of the actual force values of pressing the pads on the wheels for wagons with axial load (230.5 - 294.3) kN at speeds up to 120 km/h inclusive, for which the braking distance criterion of the freight train is observed. Key words: criterion, braking efficiency, freight train, axial load, braking distance, specific braking force, calculated coefficients, actual coefficient.