Abstract: The purpose of this article is to simulate the process of transmission of L_CR waves and carry out a preliminary study on the mechanism of transmission by finite-element method. The field distribution of an L_CR wave transmitted in rails is simulated, and experiments of L_CR wave transmission are conducted. It is found that the energy-time curve on an oblique plane of the receiving block obtained with finite-element method is similar to the signals measured in experiments. Their waveforms show the same tendency: the second peak coming after the first one. From both the finite-element analysis and the experiments, it can be concluded that the L_CR wave is a special head wave formed when a longitudinal wave is incident at the first critical angle. It is related to the finite-dimension rather than infinite-dimension of the media of the transducer generating ultrasonic waves as well as the material being measured.