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The objective of this work is to evaluate the influence of a series connected spring deflection rate with a hydraulic vibration damper on the dissipative forces of the damper and the dynamics coefficients in the first level of the rail vehicle spring suspension. The object of research is а single-axle three-mass model with two spring suspension levels which corresponds to a four-axle section of an electric freight locomotive. The vertical vibrations of the rolling stock car body, bogies and wheelsets are simulated with a random kinematic disturbance which is the rail irregularities. These simulations perform with two design variants of the spring suspension stage: with a conventional and an elastic-protected hydraulic damper. The simulation also takes into account the elastic and dissipative properties of the track under the wheelset. The perturbation was determined by expressions of the spectral densities of irregularities separately for the low-frequency and high-frequency ranges. The solution of the vibration equations is performed in the frequency domain with the determination of the real, imaginary and amplitude frequency characteristics of the dissipative forces of conventional and elastically protected hydraulic vibration dampers linking the kinematic perturbation with a change in the forces of these dampers. The effectiveness of series connected spring with a hydraulic vibration damper was verified based on a study of the dynamic properties of a simplified three-mass model of a locomotive with a standard and elastically protected vibration dampers. In addition, based on a study of random processes of vertical vibrations of such a model, the values of the dynamic quality parameters were determined, as well as the maximum dynamic forces acting on the dampers. Based on the calculation results, conclusions were made about a significant decrease in the dynamic forces in the elastically protected damper compared to the standard one with an insignificant deterioration in the dynamic quality parameters, which in both calculation options do not exceed their permissible values. It is recommended that the final conclusions be made after solving the problem of optimizing the parameters of the spring suspension on a full-size model of the vehicle.

In this article, the problem of assessing the stability of a continuous welded rail track during its thermal elongation is considered. The article considers the method of determining a stress-strain state of continuous welded rails proposed by specialists of JSC “VNIKTI”, which is based on the use of the dependence of natural frequencies of rail vibrations on the applied longitudinal force. Such a dependence can be obtained with the help of the calculation method using a finite element model of a track section. The reliability of such a dependence can be assessed by comparing the results obtained using the calculation method with the actual values of natural frequencies of rail vibrations, depending on the longitudinal tensile and compression force applied to a full-scale facility. The track panel is chosen as such a facility. In order to obtain the actual dependence of natural frequencies of rail vibrations on the applied longitudinal force, a specialized test bench is developed. The development of the test bench included designing the test bench elements and creating finite element models of main load-bearing elements of the test bench - a stop, support and traction, as well as their subsequent strength calculation to confirm the operability of the selected design under necessary loading conditions. The strength is assessed using the safety factor for the yield strength. Calculations using the finite element method have shown that the test bench design has sufficient strength. The developed test bench will allow performing tests for the purpose of the verification obtained using the calculation method of the dependence of rail vibration frequencies on the longitudinal tension and compression force applied to it, as well as for testing the proposed method to assess the rail longitudinal force during its thermal expansion.