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The article is devoted to the analysis of the quality of materials for the manufacture of fasteners for rolling stock. The paper presents the results of studies of parts destroyed during operation that are used for fastening the undercarriage assemblies, spring suspension and impact-traction devices of rolling stock. The purpose of the work is to establish the probable causes of the destruction of parts under the action of static and dynamic loads during movement on the track. The paper describes the methodology and sequence of examination of materials based on the analysis of the chemical composition of metals, the assessment of mechanical properties and the study of the surfaces of fractures of parts. The results of spectral analysis of the metal of the investigated parts, measurements of hardness and analysis of the surface of fractures of the parts are presented, which allowed to establish the possible nature, sequence and causes of their destruction. The results obtained in the course of the research showed that the main reason for the breaks in the fasteners of rolling stock is the impact on them of loads exceeding the tensile strength of the metal. It was found that the brand used in the production of metal does not meet the requirements of the normative-technical documentation for the product and is not intended for the manufacture of fasteners. Thus, the findings confirm the need to tighten the quality control of materials used in the manufacture of fasteners for rolling stock, and can be used in machine-building enterprises specializing in the production of components and spare parts for railway rolling stock. The main conclusion of the work is the need to use in the production of fastening parts of the responsible components and assemblies of rolling stock, structurally reasonable steels and alloys.

The article is devoted to the development of a methodology for monitoring the alignment and radial runout of the inner cylindrical seating surfaces of locomotive motor-axle bearings. The main reasons for the wear of the working surfaces of the bearings and the consequences of the influence of the clearances in the interfaces of the plain bearings and the axles of the wheelsets on the increase in the intensity of wear of the parts and the deterioration of the dynamic characteristics of the running gear of the locomotive are listed. The paper presents a basic diagram of the basing and control of deviations from alignment and radial runout of the inner cylindrical surfaces of bearings, describes the design and principle of operation of a special control device for measuring these deviations. The purpose of the work is to substantiate the feasibility of monitoring deviations from the shape and location of surfaces during the repair of motor-axial bearings. The paper describes the sequence of steps for measuring the alignment and radial runout of bearings and the interpretation of the measurement results. The features of the design of the control device are considered, the advantages of its use are listed in comparison with the existing analogues of the devices used to control the alignment of the holes of the body parts located on the same axis. At the same time, it was found that the control of alignment and radial runout must be carried out in order to assess the possible degree of misalignment of the traction motor frame and the axle of the wheelset of the locomotive after repair. Thus, the conclusions obtained confirm the need to tighten quality control of the restoration of locomotive motor-axle bearings by introducing into the production process the operations to control the alignment and radial runout of motor-axle necks and motor-axle bearing liners made of lead bronze, tin or lead-tin babbits.