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A plane half-track model and a periodic track-substructure model are established. The spectral element method and spectral transfer matrix method are developed and applied to investigate the track decay rate (TDR) and transmission rate (TR) of the vertical rail vibrations, which can reflect the transmission characteristics in the longitudinal and downward directions, respectively. Furthermore, the effects of different track parameters on TDR and TR are investigated. The results show that the antiresonance frequency of the rail and the out-of-phase resonance frequency of the rail and sleeper form the boundary frequencies of the highattenuation zone for longwise vibration transmission, where the vibration absorption of the sleeper is significant. The downward transmissibility of vertical rail vibrations is greatest around the antiresonance frequency of the rail. Vertical rail vibrations are primarily transmitted in the downward direction at low frequencies, while they are mainly transmitted along the rail at high frequencies. Stiffer rail pads can make more vibrations transmitted downwards to the sleeper above the antiresonance frequency of the rail, while the changes of other track parameters have different effects on the transmission characteristics. Additionally, a field measurement is performed for verification, and the simulations are well consistent with measurements.

This paper is concerned with an experimental study of improved slotted stand-off layer rail dampers in reducing railway vibration and noise. To achieve the goal, based on the idea of molecular design, polyurethane/vinyl ester resin interpenetrating polymer network damping materials with high damping properties was developed in the laboratory for the material of the damping layer. The effects of vinyl ester resin and organic small molecule hybridization on the damping properties of the polyurethane/vinyl ester resin interpenetrating polymer network material were investigated. The structural style of the damper was improved for ease of installation and removal in situ. Then, these improvements of damping material and structural style were used to make optimized slotted stand-off layer dampers, which were applied in a test section. The measurements indicate that the structural style improvement could improve the application convenience while also maintaining the noise reduction effect. The improved rail dampers could greatly increase the track decay rate at frequencies above 100 Hz and reduce noise levels by up to 6 dB at the speed of 60 km/h.

The Cologne-egg fastening systems applied in metro lines, which can be subjected to rail corrugation, are considered in this paper. To understand the mechanism of the formation and development of rail corrugation, dynamic models of the wheel and the track with Cologne-egg fastening system in the frequency domain are developed to analyse the wheel and track vibration behaviour. A field test is also analysed to verify the validity of the mechanism. Using these experimental and theoretical results, the vibration mode of the rail that is responsible for rail corrugation is determined. Based on the results, a novel rail damper that can suppress the track pinned-pinned resonance and smooth the track receptance is presented to minimize short-pitch rail corrugation. It is ultimately found from theoretical simulation and experimental investigation that the application of the rail damper is a long-term and effective method of controlling short-pitch rail corrugation in metro lines.

The problem of ambient vibration caused by rail transit continues to grow, and control effect requirements of different vibration reduction measures are always increasing. A new kind of vibration isolator used for floating slab tracks (FST) has been developed, called a metabarrier. Based on the bandgap properties of phononic crystals, it can realize a better vibration reduction capacity in certain frequency ranges with the same vertical stiffness as the original device. In order to study the vibration reduction characteristics of metabarriers under actual train loading action, two vibration isolators—a steel-spring vibration isolator and a metabarrier—were used to establish a train–FST–substrate dynamic coupling model. This study shows that the reduction capacity influenced by the phononic crystal bandgap is stable under different train speeds. In addition, under train load, the metabarrier can be used not only to isolate vibration by means of the bandgap, but also to absorb vibration dynamically, further expanding the vibration reduction frequency range. With optimized frequency range, metabarriers can reduce the acceleration vibration level by more than 9 dB over steel-spring vibration isolators.