Influence of wheel web structure on the tight-curve short-pitch corrugation of metro

Short-pitch corrugation is a common phenomenon that occurs on tight-curve rails in metro systems. However, the contributing factors of this problem are still not fully understood, and effective control measures have yet to be developed. In this study, we investigated the contributing factors of short-pitch corrugation on tight-curve rails in metro systems using the complex eigenvalue analysis method according to the theory of friction-induced vibration. We also explored control measures for short-pitch corrugation from the perspective of optimizing the wheel web structure. Our results indicate that friction-induced vibration is the primary contributing factor to short-pitch corrugation in the wheel-rail system. The shape of the web structure significantly affects rail corrugation, and compared to the straight web structure, unstable vibrations are more pronounced in the S-shape web structure. In contrast, the bow web structure can significantly improve the system stability of the wheel-rail interaction, and the greater the web curvature, the better the inhibitory effect. The wheel deformation under contact force varies with the web curvature, and when the axial deformation of the wheel extends toward the inner rail, the wheel-rail system no longer exhibits unstable vibrations. Conversely, when the axial deformation of the wheel extends toward the outer rail, the greater the deformation, the greater the instability of the wheel-rail system.