  The aim of this paper is to evaluate the train/track induced loads on the
substructure by modelling the wheel, at each instant, as a moving sinusoidal
pulse applied in a very short period of time. This assumption has the advantage
of being more realistic as it reduces the impact of time on the load
definition. To that end, mass, stiffness, and dumping matrices of an elementary
section of track will be determined. As a result, the equations of motion of a
section of track subjected to a sinusoidal pulse and a rectangular pulse
respectively is concluded. Two numerical methods of resolution of that
equation, depending on the nature of the dumping matrix, will be presented. The
computation results will be compared in order to conclude about the relevance
of that load model. This approach is used in order to assess the nature and the
value of the loads received by the substructure.
