Polymers penetrate more and more into areas of applications which were previously only reserved for metallic materials. One of these applications includes rail fastening systems. In addition, new methods and tools to support the product development process in the field of injection moulded parts have gained considerable importance. The purpose of this study was a shape optimization and design of a guide angle plate for a rail fastening system, using the finite elements method. The project was developed in cooperation with Semperit Technische Produkte GmbH (Wimpassing, AUT). The rail fastening system consists of a threshold, which supports the rail and transfers their loads to the track-structure and ensures the gauge. The threshold has two W-shaped depressions to accommodate the angled guide plates. Between such a guide angle plate pair stands the rail, which is separated from ground with a rail liner directly on the entire width of the concrete sleeper. The guide angle plates and associated clamps are screwed with two coach screws into the plastic anchors of the threshold. The aim of this thesis was to develop a simulation model for a shape optimization of the angular guide plate for mounting the track superstructure system. In order to determine the simulation model, the method of finite elements was used. It is a finite-element system, consisting of angular guide plate, tension clamp, rail liner, and threshold. In the course of the work, material and component testing was performed to obtain a verification of the simulation results. The sizing of the angular guide plate was studied taking into consideration of selected load cases and operating conditions. Based on the data obtained from the simulations a proposal for a shape optimization was achieved. Although the entire track body was not simulated, an approximation of it was found by assuming certain boundary conditions. A detailed analysis and component testing of the optimized angle guide plate are not performed in this work.