Impact of railroad switches on rail noise exposure near stations

Abstract

According to Common NOise aSSessment methOdS in EUrope (CNOSSOS-EU) in Annex II of Directive 2002/49/EC, noise from road, rail and airplane traffic, as well as noise from industries, shall be assessed using this common method. For railway noise in Sweden, noise assessment has previously been done using the Nordic Assesment Method for Train Noise, revised 1996 (NMT96). NMT96 includes a simple correction for rail joints of +3dB and for rail switches of +6dB. CNOSSOS-EU instead introduces a speed dependent correction based on a third octave band wavelength spectrum adding up to 20dB rolling noise energy in lower frequencies and down to -40 dB in higher frequencies. Measurements recently performed for two different rail switch types along the Swedish rail system indicate that the frequency distribution corresponds well to the CNOSSOS-EU correction for one type of rail switch but not for the other, and for the overall level difference the opposite is true. In order to investigate to what extent this deviation is affecting noise exposure an inventory of more than 11000 rail switches along the swedish railroad network has been performed to identify what types are situated in densely populated areas such as railway stations.