High speed trains, when crossing regions with abrupt changes in vertical stiffness
of the track and/or subsoil, may generate excessive ground and track vibrations. There is an
urgent need for specific analyses of this problem so as to allow reliable esimates of vibration
amplitude. Full understanding of these phenomena will lead to new construction solutions
and mitigation of undesirable features. In this paper analytical transient solutions of dynamic
response of one-dimensional systems with sudden change of foundation stiffness are derived.
Results are expressed in terms of vertical displacement. Sensitivity analysis of the response
amplitude is also performed. The analytical expressions presented herein, to the authors’
knowledge, have not been published yet. Although related to one-dimensional cases, they can
give useful insight into the problem. Nevertheless, in order to obtain realistic response, vehicle-
rail interaction cannot be omitted. Results and conclusions are confirmed using general
purpose commercial software ANSYS. In conclusion, this work contributes to a better understanding
of the additional vibration phenomenon due to vertical stiffness variation, permitting
better control of the train velocity and optimization of the track design
