This paper deals with the pressure waves generated by a train running through a short tunnel and radiated from its portals to surrounding areas as infrasound. First described are the results of a field measurement conducted at a short, 93 m-long, Shinkansen tunnel to present the generation mechanism of the infrasound. Next an acoustic analysis is made of the infrasound radiated to the outside by applying a method for predicting the compression wave in the tunnel generated by train entry. The calculated and measured results of the waveform of the infrasound are consistent despite considerable simplification in geometric modeling in the analysis. Comparison of the spectra shows that the acoustic analysis is capable of calculating the components below about 10 Hz of the infrasound, including the harmonics of the fundamental frequency of 1.7 Hz determined from the tunnel length.
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