In the present study, dynamic vibration absorber (DVA) has been introduced as an innovative countermeasure in the field of railway-induced vibration. The Pipe-in-Pipe (PiP) model and Green's functions for a two-and-a-half dimensional (2.5D) elastodynamic problem in a full- and half-space have been employed to find the response of the tunnel embedded in a homogeneous half-space due to a harmonic load. DVAs have been coupled to the tunnel interior surface. The effectiveness of DVAs depends on the mass, damping ratio, natural frequency and their distribution. Therefore, an optimization algorithm has been developed to find the optimum parameters of the DVAs, which are those that minimize the vibration levels at the ground surface. Evaluating the efficiency of the optimal DVAs shows that they are an efficient countermeasure to mitigate underground railway-induced vibration.