In this dissertation a review of the issues in traction system that can have an impact on energy consumption in this system is presented first. A simulation model of the train movement and impedance catenary are displayed in detail in chapter three as well as the parametric analysis of the influencing factors on energy consumption for one type of the train. Both models are verified with experimental measurements in 25 kV AC traction system. In the fourth chapter of the dissertation, there is an elaborate presentation of the "modified SQP-method" phases, since the method is used to optimize electric train energy consumption. A flow chart for this method is also given. The fifth chapter offers a test of the method on a passenger train that weighs 135 tons on a railway route whose total length is 4.8 kilometers. The results of the test case show that the developed "modified SQP-method" based on sequential quadratic programming is suitable for the optimization of the energy consumed by electrical trains. After evaluating the accuracy of methods on the test case, the developed method is applied to real cases of energy consumption optimization for traction passenger and freight trains. The sixth chapter presents the results of "modified SQP-method” for optimization of active energy consumed during the traction power supply. The conclusion puts an accent on the effective application of the developed "modified SQP-method" specifically for railways on which freight trains operate.