Identification, modelling and reduction potential of railway noise sources: a critical survey

Environmental requirements for railway operations will become tighter in the future. In particular, annoyance due to railway noise has to be taken carefully into account in the expansion of freight traffic as well as in new high speed line projects. Reduction of noise at source can be more attractive than the use of noise barriers but this requires a thorough understanding of the source mechanisms. This paper presents a critical survey of the identification and modelling of railway noise sources and summarizes the current knowledge of the physical source phenomena (mainly rolling and aerodynamic sources) as well as the potential for noise reduction. Future research perspectives are also given. These concern, in particular, improvements to source modelling, especially for aerodynamic noise, investigation of other sources and development of more advanced models for predicting railway noise in the environment. These should include a better description of the sources, obtained from modelling

Railway source models for integration in the new European noise prediction method proposed in Harmonoise

The purpose of the Harmonoise European project is to provide an engineering model for the propagation of road and rail traffic noise which requires, for a better accuracy than existing models, the distinction between source output and propagation. In that context, the purpose of work package 1.2 of Harmonoise is to provide the emission data for railway sources to be implemented in the engineering model for the propagation. The relevant output of the emission data that is useful as input of the propagation calculations is the sound power level of equivalent moving point sources for at most five fixed heights and the associated directivity, both in one-third octave bands. The purpose of Harmonoise is to provide source models based on the most relevant physical parameters which can describe the three main sources: rolling, traction and aerodynamic. A database structure with some examples is also provided as well as guidelines for practical data collection. The paper presents first the main investigations which have been carried out through Harmonoise to provide the source models based on their physical parameters. The paper also presents how the database is organised and linked with the Harmonoise engineering model