Noise prediction of trains in curves [thesis]

Michael Ostermann, Norbert Ostermann
People become more and more aware of noise and noise regulation thresholds decrease to satisfy the needs of a quiet environment, while also preventing health issues due to noise pollution.Avoidance of noise as a limiting factor in train operation results in a huge investment regardingnoise mitigation measures, which raises building and maintenance costs significantly. Thus,noise prediction to plan mitigation measures adequately and cost-efficiently is going to become essential. Although
more » ... l. Although standards for calculating the noise emission of trains were developed insome countries in Europe, the elevated noise emission in curves is either considered with a single additive factor dependent on the radius or not considered at all. Hence, neither higher rolling noise in curves nor curve squeal, which states one of the most disturbing noise source semitted from railways, is sufficiently accounted in current noise emission models. The present thesis investigates influence factors on frequency of occurrence, peak levels and relative occurrence time of three distinguished curve squeal types as well as on general noise emission incurves. Examinations are carried out empirically and statistically using sound measurements of train pass bys collected in five different sections in the Austrian heavy rail network with radii between 226 m and 440 m and speed limits between 60 kmh-1 and 90 kmh-1. After datafiltering, 29097 train pass bys are considered in the final evaluation. An empirically elaboratedalgorithm detects time increments containing curve squeal (distinguished in all three stated types) out of short-time averaged (64 ms) third-octave band time spectra. Influence examination considers a total of 190 parameters, which are grouped in five categories – track,vehicle, dynamic, general and environmental. Main findings on frequency of occurrence are a high impact of relative rail humidity with peaking probabilities between 72 % and 75 % for all three types and decreasing rates in both directions in the remaining area, partly distin [...]
doi:10.34726/hss.2021.91123 fatcat:abo3u7s7enedrph2xopmjvpi2a