COMPREHENSIVE ANALYSIS OF THE OPERATIONAL PERFORMANCE OF BRAKE SHOES FOR PASSENGER RAILWAY VEHICLES

Abstract

The paper addresses the problem of improving the efficiency of railway rolling stock braking systems through a comprehensive analysis of the design, tribological, thermal, operational, and economic characteristics of modern brake blocks. The performance of the braking system is largely determined by the frictional properties of brake blocks, which directly affect braking efficiency, braking distance, wheel wear, maintenance costs, and the overall operational safety of railway vehicles. The increasing axle loads, higher train speeds, and more demanding operating conditions require the development and application of friction materials capable of maintaining stable braking performance under a wide range of service conditions.A comparative analysis of cast iron, high-phosphorus cast iron, composite, and sintered metal brake blocks was carried out. Their structural features, frictional properties, thermal behavior, durability, advantages, disadvantages, and fields of practical application were evaluated. Particular attention was paid to the comparison of traditional cast iron brake blocks with modern composite brake blocks, which have become widely used in freight and passenger rolling stock due to their improved wear resistance, lower weight, and higher friction coefficient.A comprehensive approach for evaluating the operational efficiency of railway brake blocks is proposed. Unlike conventional methods, which mainly focus on separate tribological characteristics, the proposed approach simultaneously considers the coefficient of friction, wear resistance, thermal conductivity, required application force, brake cylinder pressure, loading of brake rigging components, compressed air consumption, service life, purchase cost, maintenance costs, and overall economic efficiency. Such an integrated assessment makes it possible to determine the rational application area of each brake block type depending on operating conditions and technical requirements.The study has shown that composite brake blocks provide a friction coefficient approximately 20-40 % higher than that of conventional cast iron brake blocks, allowing the required braking force to be achieved with a 20-30 % lower application force. As a result, the load acting on the brake rigging, brake cylinder, and pneumatic braking equipment is reduced, while compressed air consumption and maintenance costs decrease. Furthermore, the service life of composite brake blocks exceeds that of cast iron blocks by approximately three to five times, leading to lower life-cycle operating costs despite their higher initial purchase price.At the same time, the lower thermal conductivity of composite friction materials results in increased temperatures at the wheel-brake block contact interface. This phenomenon raises the probability of thermal defects, wheel tread damage, and thermomechanical deterioration of wheelsets during intensive braking. Therefore, when selecting brake block materials, both braking efficiency and thermal loading of wheelsets should be considered. The obtained results can serve as a scientific basis for selecting brake block materials during the design, modernization, and operation of railway braking systems and may contribute to improving operational reliability, reducing maintenance costs, and increasing traffic safety.