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Rail corrugation is very common in metro systems, and serious noise problems produced by rail corrugation, especially short-wavelength corrugations (25–50 mm), are a common cause of passenger complaints. For metro trains, the wheel-rail interface is the main source of noise, and the wheel-rail roughness, especially in the presence of rail corrugation, is the main excitation source. Rail grinding is a fast, economical, and effective control measure for reducing vibration and noise. However, the existing grinding cycle is not sufficient to meet the requirements of interior noise. There is no rail grinding standard based on interior noise limits for metro trains running on slab tracks in tunnels, which covers the vast majority of situations in China. Therefore, there is an urgent need to understand the effects of rail corrugation on interior noise for metro trains running on slab tracks in tunnels. At the same time, a rail grinding standard based on interior noise limits for such metro trains is very important. In this paper, the characteristics of the serious noise problems caused by rail corrugation are identified and suitable rail grinding controls based on noise limits are presented. [ABSTRACT FROM AUTHOR]

This paper presents a detailed Statistical Energy Analysis (SEA) and contribution analysis of the interior noise of a high-speed train through extensive simulations and measurements. The SEA model was developed based on the actual geometrical parameters of a benchmark high-speed coach. Sound transmission loss levels of the structural components of the car body, which are required in the SEA model, were tested in a dedicated acoustic laboratory following international standard ISO 140-3:1995. Modal densities of these structural components were derived from measured frequency response functions using the modal counting method. Damping loss factors were obtained using the half-power bandwidth method and the vibration attenuation method. By considering the relationship between sound radiation and power transmission, coupling loss factors between structures and cavities were estimated. Source inputs to the SEA model were derived from field experiment data. Interior noise due to those sources was predicted using the SEA model and the prediction was generally in good agreement with measurement. Contribution analysis was then performed using this validated model through parametric study, and this analysis was further examined experimentally. In conclusion, for the coach that was investigated in this paper, the key factors for interior noise are sidewall vibration, bogie area noise, and floor sound transmission loss. Based on this and other engineering considerations, an interior noise control strategy can be defined. [ABSTRACT FROM AUTHOR]

• Propose an acoustic design procedure for controlling interior noise of rail vehicle. • The procedure is applied to the design of Chinese 'Fuxing' high-speed train. • The design goal of 3 dBA interior noise reduction has been achieved. • The modelling method of interior noise based on experimental SEA is put forward. • Both in-situ measurements and simulation analyses are used to study the issue. Excessive interior noise in high-speed trains affects riding comfort of both drivers and passengers, therefore, it is a key indicator of product competitiveness for manufacturers. Past academic researches on train interior noise control focus primarily on mechanisms and characterisations of noise sources and vibro-acoustical behaviours of car-body structures, and these two aspects are often dealt with separately, unable to lead a systematic procedure for controlling high-speed train interior noise. On the other hand, many practical studies are problem-based, aiming at finding root causes of, and remedies for, a noise problem which has already occurred. They not only lack of systematisms, but also are time- and resource-consuming. To design low interior noise and to make sure the actual product based on the design does meet noise target, an acoustic design procedure is needed. Based on the experience of many years' research in the field of railway noise and vibration, especially that gained in the development of the Chinese 'Fuxing' high-speed trains, such an acoustic design procedure for interior noise is summed up and described in this paper. Application of the procedure to the development of a to-be made high-speed train is also presented, together with results simulated and measured on the developed train, showing that the design goal of 3 dBA noise reduction is met. [ABSTRACT FROM AUTHOR]

With urban rail transit developing fast, there is an increasing demand for riding comfort and reduction of vibration and noise. Metro being the main public transportation facility of urban rail transit in China, faces more severe challenges. Metro tracks use a range of different vibration isolating ballasted track structures. Environmental vibration along metro lines is controlled by using so-called vibration isolating track structures. In doing so, many problems arise in the train-track system of metro lines, such as strong vibration and excessive wear of wheel/rail systems, causing vibration fatigue and noise. Embedded track is used as an option to reduce vibration and noise, usually applied for tramways. When applied to metro lines, embedded track faces challenge due to high speed, large axle load and more complex line conditions. When applied to metro lines, the acoustic characteristics of embedded track need to be re-evaluated. These characteristics were investigated through a combined method of simulation and experiment. In this study, the wheel and track acoustic radiation of the embedded track designed for metro is predicted firstly. Then the tests of vibration and acoustic of the embedded track are carried out to verify the accuracy of the model on the one hand, and compare with the common fastener track to obtain more aspects of vibration and noise on the other hand. This study can provide a basis for the application of embedded track in metro systems. [ABSTRACT FROM AUTHOR]