Recent developments in noise research at Deutsche Bahn (noise assessment, noise source localization and specially monitored track)

Abstract To strengthen the environmental friendliness of railway traffic in Germany, Deutsche Bahn (DB) is in the process of performing a major research programme concerning noise reduction. To realize this, the DB ‘Low Noise Railway’ programme deals simultaneously with the noise treatment of trains and the wheel/rail system as well as other topics. The assessment of a particular sound experience as annoying noise is a very personal judgement and cannot be dealt with by physical quantities alone. To permit a better understanding of this phenomenon and to support the legislative authorities, the assessment of noise quality is being investigated in detail. To reduce railway noise, the exact location and the magnitude of the different sound sources have to be known. This can be analyzed with an array of many microphones which has been developed by DB in the last few years. Most recently, DB has developed the acoustic concept of the ‘Specially Monitored Track (SMT)’ into a practical application and is now starting to upgrade SMT to increased performance and at a lower cost.