In recent years, railway vehicles are becoming lighter since it corresponds to improvement on the running speed. However, this affects degree of ride comfort as the increase of bending vibration for due to the deterioration of the body rigidity. Recently the piezo-electric elements are paid attention as an actuator for structures in order to control vibration. This is referred as the smart structure concept. A piezo-electric element has characteristic that is small, light and high output. Therefore, the objective of this research is to reduce bending vibration by embedding piezo-electric element in the body. Consegueutly, the experimental setup is built up which can simulate bending vibration with consistency to simulation. And, the effectiveness of the controller designed by using the H_∞ control theory is verified. In this report, the effect of the vibration control by varying the installation position of the piezoelectric element is examined.