  In the present paper, the effects of focusing of Rayleigh waves generated by
high speed trains in the supporting ground under the condition of ground
vibration boom are considered theoretically. These effects are similar to the
effects of focusing of sound waves radiated by aircraft under the condition of
sonic boom. In particular, if a railway track has a bend to provide the
possibility of changing direction of train movement, the Rayleigh surface waves
generated by high-speed trains under the condition of ground vibration boom may
become focused. This results in concentration of their energy along a simple
caustic line at one side of the track and in the corresponding increase in
ground vibration amplitudes. The effect of focusing of Rayleigh waves may occur
also if a train moves along a straight line with acceleration and its current
speed is higher than Rayleigh wave velocity in the ground. The obtained results
are illustrated by numerical calculations.
