Critical speed of railway tracks. Detailed and simplified approaches

The dynamic amplification effects of the response due to a moving load on the surface of an elastic solid has been object of research for more than a century. However, if in the beginning of the last century the problem had only theoretical interest, this is no longer true. Indeed, the recent advancements in the rolling stock, which can now reach speeds higher than 500 km/h, brought this kind of problems to the engineering practice, mainly to high speed railway engineering. The present paper approaches this problem focusing on railway engineering. The departing point is the theoretical formulation of the critical speed problem of a moving load on the surface of an elastic solid. From the usage of 2.5D detailed models it was possible to understand the influence of the embankment and track properties on the critical speed. However, to avoid complex numerical models, which are very demanding from the computational point of view, a simplified approach is proposed for the computation of the critical speed of track–embankment–ground systems. The results of the simplified approach are compared to those achieved by detailed methods, also presented in this paper, and the proposed expedite methodology is found to be very accurate.