AbstractAn analysis is made of the problem of vibrations of a beam on elastic foundation, when the beam is of infinite length and is subjected to an alternating load which moves with constant velocity along the beam. The solution is presented within the framework of a beam theory which includes the effects of shear deformation and rotary inertia. Critical characteristic parameters of the system are defined. An example is provided where the displacement and the bending moment are calculated. From the results of theoretical analysis, it becomes evident that the frequency of the load has considerable effect upon the dynamical behaviour of the system.