Effects of train impacts on urban turnouts: modelling and validation through measurements

Train–track interaction at turnouts is a main issue in the design and maintenance of railway systems. Due to the particular geometry of wheel–rail contact and to the sudden variation of track flexibility, severe impact loads may occur during train passage over the turnout. In this paper, two different modelling approaches to reproduce train–turnout interaction are proposed and compared. A first technique, developed by Politecnico di Milano, is based on a detailed multi-body model of the trainset and of wheel–rail contact, whereas for the turnout structure a simplified finite element model is used. The second modelling technique, developed by the National Technical University of Athens, relies on a detailed finite element model of the turnout, while a simplified model is used to compute impact loading due to wheel passage. In this paper the two methods are validated trough comparison with line measurements performed on turnout systems from three different urban railway networks.