LAUSR

Abstract In high-speed railway tracks, deterioration of the ballast layer and consequent impact on track geometry is the leading source of track maintenance costs. To mitigate these issues, installing under-sleeper pads (USPs) is becoming a usual strategy mainly in high-speed lines to reduce degradation rates and cut maintenance costs. However, the design of railway tracks equipped with USPs must be based on rational design processes which should take into account the impact on dynamic response of installing particular combinations of flexible track components. Within the framework of the European project Capacity4Rail (C4R), this paper shows some results obtained in a numerical model, based on a laboratory test case from CEDEX on its Track Box laboratory facility, so as to simulate and test different design solutions to upgrade track performance at very high speeds. An optimisation procedure was computed to select combinations of railpads and USPs which improves the dynamic response of the reference railway track. Results show that selected combinations of railpads and USPs lead to potential reductions of around 30% in peak vertical ballast acceleration values caused by train moving at speeds ranging from 300 to 400 km/h when compared to a reference track with no use of USPs.