Abstarct: In recent decades, the use of railway transport infrastructures has increased because of high safety, efficiency and little effects on the environment. This has led human to think about ways to speed up, increasing the capacity of cargos and better use of the trains. Due to the extreme limitations of ballasted tracks (e.g., speed and capacity limitations, etc.) and the high cost of repairing these tracks, using of slab tracks was replaced. Increased usage of slab tracks brought new challenges in railway track dynamics that requires a better understanding of it. The aim of this thesis is to study the effects of dimensional and mechanical parameters of the track components (including the thickness of laxyers, elasticity modulus of laxyers, the distance of sleepers and fastenings and width of the subsoil laxyer) on vertical dynamic response of a three-dimensional model using the finite element method (FEM) with ABAQUS/CAE. Because of existence of varieties of slab tracks, two of the most widely used tracks in the world (Rheda 2000 and Shinkansen) has been studied. The finite element analysis was done baxsed into two categories: eigenvalue analysis and steady-state dynamic analysis. The natural frequencies and corresponding vibration modes were extracted by using eigenvalue analysis and then by using steady-state dynamic analysis, frequency response functions of the track extracted. Track components have been studied separately, and a comparison between the effects of the laxyers on the dynamic behavior of track was investigated. The results of this thesis shows that by decreasing the elasticity modulus of the track components leads to decreased resonance frequencies and increased vertical frequency responses of the track. Besides, increasing the thickness of laxyers leads to increased resonance frequencies and decreased vertical frequency response of the track. Elasticity modulus of HBL in Rheda 2000 and Shinkansen, the thickness of CBL in Rheda 2000 and thickness of HBL in Shinkansen are parameters which have the most effects on the dynamic behavior of this slab tracks.