This master thesis is concerned with the determination of adjustment factors for simplified consideration of the train-bridge interaction for the high-speed railway bridges. As part of the thesis, a parametric study is performed with the purpose to determine the difference in the structural response between the travelling loads model and the detailed multi-body model. Based on the results of the parametric study, the adjustment factors for examined bridges are calculated. The adjustment factors allow a correction of the results of travelling loads model, so these approximate the results of a detailed multi-body train model. There were studied two possibilities for customization of the system response: an adjustment within a certain span L and an adjustment between different spans L. Finally, the formulas for estimating the adjustment factors were derived, which are designed to simplify an application in practice.