Abstract: Haulage installations are subjected to many efforts making their equilibrium difficult in spite, the use of equilibrium devices. In this study a mathematical model of this type of installation is developed and studied taking in consideration the factor of traction cable elasticity (dumping factor). If the dumping factor (or attenuation) of oscillations goes beyond a certain limit, this will provoke a fast and a considerable propagation of elastic deformations along the cables (on all their length) which unbalances the installation operation.