Wave problems in high-speed railway tunnels

When a high-speed railway train enters a tunnel, a compression wave is generated and propagates along the tunnel. The compression wave is reflected back at the exit and an impulsive wave is emitted outward. This paper deals with some subjects concerning the waves of railway train-tunnel systems, i.e., an entry compression wave, the attenuation of the compression wave propagating along the tunnel, and the generation of an impulsive wave at the exit portal of the tunnel, focusing our attention to the alleviation of the impulsive noises from the tunnel exit.