Abstract: Solidworks software is adopted to construct WJ-2 elastic rod 3D finite element model. Analysis of the intrinsic frequency and vibration type of the elastic rod in free state and standard installation state is carried out. It is found that the elastic rod can easily cause resonance when being in service and consistent with wheel-rail corrugation excitation, and its resonance frequency domain is at the tail supporting position, same as the fracture position on site. Based on this, under the premises of no impact on the auxiliary facilities of WJ-2 rod fastener, an optimization design of the elastic rod structure is carried out. Simulation analysis is conducted respectively on the three working conditions of rod filled no damping material after the inner canvity is emptied, filled with rubber, filled with ferrite ductile iron. Results show that when the elastic rod cavity is filled with ferrosteel, the vibration reduction effect is good, while mechanical performance is under expectation. When the rod cavity is filled with ferrite ductile iron, the mechanical performance is good while the convergence effect is not evident as well.