Improving rolling noise predictions for new track designs

Railway rolling noise dedicated software such as TWINS or STARDAMP perform reliable predictions for vehicles operating on tracks whose wave decay rates have been measured experimentally. On the other hand, accurate noise predictions of new track designs are difficult to achieve due to the limitations of TWINS to perform a precise estimation of vertical and lateral wave decay rates along the rail.A numerical approach allowing to improve TWINS ability to predict rolling noise related to new track designs is proposed and validated in this paper.Firstly, limitations of TWINS track models are discussed and ways of improvement are pointed out.Then, a numerical approach to compute vertical and lateral wave propagation along the rail is proposed. This approach is based on the development of track F.E. models. It consists in replacing the actual measurement procedure by a 'virtual' measurement procedure on a 'virtual track'.Comparisons between measured and computed decay rates in third octave bands are then presented for several track designs; the good correspondence between measurements and predictions confirm the relevance of the method.