Vol 83, No 2 (2024)

Introduction. A number of design features of the rolling stock and operating conditions of the SA-3 automatic coupler in locomotive traction passenger cars cause increased wear of the rubbing surfaces of the automatic coupler, which requires measures to strengthen them. The issue of automatic coupler loading for wagons is studied and presented in research, technical and regulatory documentation. The authors consider the experimental data on longitudinal forces and relative displacements of automatic couplers under operating modes to be insufficient in the case of the SA-3 automatic coupler in a locomotive traction passenger car. Lack of such studies did not allow manufacturers of SA-3 automatic couplers intended for use in passenger rolling stock to reasonably implement processes for hardening of contact surfaces. The study was primarily intended to obtain reliable experimental data on the relative displacements of automatic couplers during motion as part of a passenger train, as well as on the acting longitudinal forces.

Materials and methods. The main method of the research was direct measurements of relative displacements using contact displacement sensors. Longitudinal forces were determined by resistance strain gauges mounted on the automatic coupler body. The test ride was preceded by scaling of the measuring circuits by tensile and compressive forces using the bench equipment of the test laboratory of the Tikhvin Trial Centre for Railway Transport.

Results. The authors obtained statistically reliable data on longitudinal forces and displacements of automatic couplers when the carriage moves in a locomotive traction passenger train.

Discussion and conclusion. The authors determined the longitudinal forces and displacements of the SA-3 automatic coupler used in a locomotive traction passenger car. These data are intended for further use in bench service life testing of the automatic coupler.

Introduction. The problem of contact fatigue damage of rails has become especially urgent with the intensified railway freight load. An effective method of studying various damage factors is mathematical simulation of the dynamics of motion and accumulation of contact fatigue damage in the rail material. The damage accumulation simulation uses a curve of dependence of the number of wheel loading cycles or design rail section until contact fatigue failure on the value of the selected contact fatigue criterion. This curve could only be obtained in an experiment.

Materials and methods. The authors performed bench-scale contact fatigue testing of roller-shape rail steel specimens. The test rig of original design created a load of up to 4000 N on the rollers. The experimental data were processed using the finite element method. The problem of rolling the specimen and the counterbody was solved in the elastoplastic formulation.

Results. The authors studied the effects of the size and shape of the contact surfaces for the contact fatigue test specimens on the distribution of contact pressures. They designed and built a roller-on-roller contact fatigue test rig. The researchers tested rail steel specimens for contact fatigue. The results were processed using the finite element method with the plotting of contact fatigue curves of rail steel according to three criteria: combined, Dang Van criterion, amplitude value of maximum shear stress.

Discussion and conclusion. The developed methodological approach yielded contact fatigue curves of rail steel. The curves may be used in simulations of the accumulation of contact fatigue damage in the rail material under different axle loads, dynamic loads arising when the rolling stock moves in curves and straight track sections with different rolling profiles of wheels and rails.

Introduction. Methods of automatic measurement of rail track joint gaps are not accurate enough or require costly equipment and sensors. This is why joint gaps are still monitored manually in many cases. The work is intended to experiment and examine a new method of automatic measurement of gaps in bolted rail joints using magnetic flaw detection (MFL).

Materials and methods. The paper uses actual track inspection results obtained by a flaw detection car on one of the railroads of Russian Railways. A specially developed programme used magnetic channel signals to highlight bolted rail joint locations and determine the magnitude of the joint gaps. The joint gaps were also measured manually using video images of bolted joints obtained by the on-board rail video recording system.

Results. The authors obtained expressions for calculating the joint gap value using magnetic sensor signals. Small gaps (up to 8 mm) are estimated by amplitude, medium and large gaps (above 9 mm) — by the spatial parameter of the signals from joint gaps. The authors compared the gap measurements from the two specified methods: visual and magnetic.

Discussion and conclusion. The research confirmed that automatic identification of bolted joints and determination of the value of joint gaps by magnetic rail flaw detection are sufficiently reliable for practical application. A comparative analysis of the values of the video inspection and the magnetic method showed high accuracy of joint gap measurement when using the latter. The magnetic method signals show high stability and repeatability.

Introduction. The article is devoted to the 100th anniversary of the birth of a major railway economist, Doctor of Economic Sciences, Professor Anatoliy Petrovich Abramov, who made a great contribution to the development of national economic science. The economists works reflect an extraordinary bright personality who left an indelible trace in the memory of those who worked with this outstanding person.

Materials and methods. The article uses facts of Anatoliy Abramov biography, memories of his colleagues at the institute, and his achievements in the form of numerous scientific publications.

Results. The article outlines the outstanding economist life journey, explores his contribution to the development of economic science in railway transport, reveals his multifaceted talent.

Discussion and conclusion. This article is an opportunity to pay tribute to the memory of Anatoliy Abramov, famous railway economist, founder and head of a scientific school and remarkable person.