Study of the Causes of Limiting Wear of Freight Car Composite Brake Blocks

The study objective is to find out and analyze the causes of limiting wear, in particular wedge shaped wear, of composite brake blocks of freight cars, which has a significant impact on traffic safety. The task the paper is devoted is to systematize the key operational, design, and engineering factors that lead to uneven wear of blocks and to analyze their impact on the operation of the braking system. The research methods include a theoretical analysis of the calculated dependencies of the braking system, the study of regulatory and technical documentation and scientific publications, as well as practical analysis of data from field observations and measurements of the geometric parameters of worn brake blocks. The novelty of the work is in the comprehensive approach to the problem of wedge shaped wear, which combines theoretical calculations of the maximum permissible forces in the braking system with the analysis of statistical data and real samples of defects. The paper systematizes the list of causes leading to this type of failure. The research results. During the study, it is found out that wedge shaped wear is the dominant defect (up to 57 % of cases) of composite brake blocks. A list of the main causes is identified and analyzed, including incorrect adjustment of the brake lever system, material quality, operating conditions, overloading of cars, and wear of associated parts, such as the brake shoe. Measurements of actual block samples confirmed the uneven nature of the wear. Conclusions. It is concluded that wedge-shaped wear is the consequence of the combined influence of multiple factors. To prevent it and improve the reliability of braking systems, a comprehensive approach is required, including strict adherence to adjustment standards, quality control of materials, and timely diagnostics of the associated components of the braking system.