This study is focused on the effects of bending and torsional flexural modes of the car body on the ride quality index of a high-speed train vehicle. The Euler–Bernoulli beam model is used to extract an analytical model for a high-speed train vehicle car body in order to investigate its bending and torsional flexural vibrations. The rigid model includes a car body, two bogie frames, and four wheelsets such that, each mass has three degrees of freedom including vertical displacement, pitch motion, and roll motion. The results obtained with the proposed analytical model are compared with experimental measurements of the car body response of a Shinkansen high-speed train. Moreover, it is determined that the bending and torsional flexural modes have significant effects on the vertical acceleration of the car body, particularly in the 9–15 Hz frequency range. Furthermore, the ride quality index is calculated according to the EN 12299 standard and it is shown that the faster the train the more affected is the ride quality by the flexural modes. In addition, the effect of coherence between two rail irregularities (the right and the left rails) on the results of the simulation is investigated. The results conclude that if the irregularities are completely correlated the torsional flexural mode of the car body does not appear in the response. Also, the first bending flexural mode in such cases is more excited compared with the partially correlated or uncorrelated rail irregularities. Therefore, the ride quality index in completely correlated cases is higher than other cases.

Wheel slip control in high-speed trains is used to reduce the acceleration time and produce the maximum traction motor power. For controlling slip in a complete model of a train consisting of the traction motors, it is needed to keep the adhesion coefficient as much as possible by controlling the input voltage. In this article, integrated sliding mode and direct torque controls are used to control the transient traction in a full model of a high-speed railcar consisting of a wagon, two bogies, four wheelsets, and four traction motors. Cosimulations in SIMPACK with MATLAB/Simulink are carried out to evaluate the performance of the designed control structure. By comparing the results of the open-loop and closed-loop simulations, it is shown the acceleration time of the high-speed railcar is decreased 26% and the production of the traction motor power is increased 32% for both dry and wet surface conditions. It is also shown that the designed control structure is stable and robust in the presence of uncertainties.

This research is concerned with bogie-carbody nonlinear dynamic interaction of a Shinkansen high-speed rail vehicle. The Euler-Bernoulli beam model is used to simulate vertical elastic vibrations of carbody. As a novelty, the traction rod that connects the bogie frame and the carbody is considered a nonlinear element. The equivalent linearization method is used to analyze the nonlinear vehicle system in the frequency domain. The analytical spectrum solution compared with the measured data from the running test and the numerical solution in the time domain. When the dynamic interaction due to the carbody's flexibility is considered as nonlinear rather than linear, the maximum amplitude of the bounce acceleration relevant to the first bending mode increases by 38.2 percent at the travel speed of 300 km/h. With the inclusion of the nonlinear interaction, ride comfort improvement is achievable. It is also feasible to manipulate the vehicle's ride comfort by altering its bogiebase.