1 INTRODUCTION The behaviour of the railway track and infrastructure under the combination of high speed and repetitive axle loadings is affected as a result of a complex soil-structure interaction problem that constitutes a motive of geotechnical and structural R&D. In fact, high speed trains bring some new problems: (1) high train speeds demand tighter tolerances and track alignment for the purpose of safe and passenger comfort; (2) after a critical speed drastic dynamic amplification appears on the deformation of the track, embankment and supporting soft soil. Proper modelling of the dynamic behaviour of the railway track system, the soil and embankment materials and of the loading is essential to obtain realistic results. Additionally, measurements on actual railway sections is necessary for monitoring of the physical behaviour of the rail track and infrastructure for the calibration of the tools. These aspects are being investigated throughout an ongoing na- tional project financed by the Foundation for Science and Technology involving the University of Minho (UM), the National Laboratory of Civil Engineering (LNEC) and the New University of Lisbon (UNL). This paper presents preliminary results obtained with modelling using different numerical tools available at the different institutions: DIANA (UM), PLAXIS (LNEC) and ANSYS (UNL). A case study of an instrumented section of a high speed line was utilized using monitor- ing results presented by (Degrande & Schillemans, 2001), in order to evaluate the performance predicted based on the models created with the abovementioned tools.. In these early studies of comparative suitability of these tools to be used in pratical applica- tions a 2D model was assumed for the analysis. As to whether 2D models are suitable for these analysis, there’s an almost unanimous agreement between researchers that while they provide some understanding of the problem, 3D models are essential to reach accurate results. Some au- thors consider a special symmetry, which they call 2.5D. Another interesting simplified ap- proach was proposed by Gardien and Stuit (2003) studying the modelling of soil vibrations from railway tunnels. These authors, instead of creating a three-dimensional model for the dynamic analysis built three complementary models: the first one is three-dimensional, where static loads were applied to obtain equivalent Timoshenko beam parameters, which are used in the second Dynamic analysis of rail track for high speed trains. 2D approach A. Gomes Correia & J. Cunha University of Minho, Department of Civil Engineering, Civil Engineering Centre, Guimarães, Portugal J. Marcelino & L. Caldeira Laboratório Nacional de Engenharia Civil, Lisboa, Portugal J. Varandas, Z. Dimitrovová, A. Antão & M. Gonçalves da Silva New University of Lisbon, Lisboa, Portugal ABSTRACT: In the framework of an ongoing national research project involving the University of Minho, the National Laboratory of Civil Engineering and the New University of Lisbon, dif- ferent commercial FEM codes (DIANA, PLAXIS and ANSYS) were tested to model the dy- namic performance of a high speed train track. Initially a plain strain model is considered in a robin test using experimental data from a well documented instrumented standard ballast rail track under the passage of a HST at 314 km/h. Numerically predicted results are presented and assessed, and comparison is made between the different codes and also the experimental data.