Generation of ground vibrations by superfast trains

Ground vibrations generated by superfast trains are studied theoretically, taking into account the contribution of each sleeper of the track subjected to the action of the carriage wheel axles. It is shown that a very large increase in vibration level may occur if the train speed exceeds the velocity of Rayleigh surface waves in the ground, a situation which might arise, for example, with TGV passenger trains for which speeds over 500 km/h have been achieved on the experimental track in France. The results are illustrated by numerically calculated graphs of spatial distributions and frequency spectra of ground vibrations generated by trains moving with different speeds. Simple mitigation measures based on waveguide effects for ground vibrations are suggested.