Abstract Software for modelling of industry processes is an integral part of production involving many segments of industry. The use of simulation software in foundry industry is perceived as a tool for visualization of ongoing processes in casting production. These tools eliminate defects and imperfections within the process before the production even begins which has a subsequent positive effect on quality increase and reduction of financial costs in product manufacturing. The paper deals with a solution of formation and occurrence of foundry defects such as shrinkage in the casting produced from ductile iron with the use of simulation software. The casting of railway brake disc and its 3D model were used in the experiments. The goal of the study was evaluation of simulation results with regard to casting quality increase and decrease of shrinkage formation, as well as decrease in manufacturing costs during casting production. The paper focuses on a possibility of improving the utilization of liquid metal in the solidification of castings with the help of simulation that compares basic as well as adjusted parameters of casting. Computer simulation of casting uncovered the gating system elements' adjustments and technological modifications effect on the entire casting and on reduction or elimination of shrinkages incidence along with the increase of liquid metal utilization during casting. These imply the reduction of financial costs and increased efficiency in production of castings. The paper presents the results of the simulation casting of the railway brake disc. Based on the results of these simulations, the shape of gating system and position of casting in mould was modified and the number of feeders has been reduced from 6 to 1. This technology modification saves the liquid metal and the casting has been without shrinkages.