Purpose: To substantiate the selection and experimental development of an accelerated fatigue test of cast load-bearing parts of the 18-9891 Model innovative bogie. Methods: The experimental study of the 18-9891-Model bogie side frames with an axle load of 25 tons (245 kN) was conducted using the Locati method. The method under discussion is based on the hypothesis of linear summation of relative fatigue damages occurring during the testing of a full-scale component under conditions of gradually increasing loads over a given period of time. Results: The fatigue test results demonstrate that the Locati method is an effective means of ensuring the parameters of the side frame fatigue curve obtained when testing a single sample. The standard fatigue testing procedure for side frames necessitates the testing of nine full-scale components. Practical significance: The implementation of a novel accelerated fatigue testing method will lead to substantial reductions in time, materials and testing resources, both during the manufacturing of prototypes and in the mass production of cast load-bearing parts for freight wagons.