One of the main problems of modern vehicle design is the reduction of energy consumption, and as a guiding thread to reduce its consumption is the reduction of the total weight of the vehicle. Currently, one of the most powerful engineering methods of reducing the mass of a structure is topological optimization. This thesis presents the concept of topological optimization applied to the roof carrier of a high voltage cable of a commercial rail vehicle and the process of preparing a topologically optimized structure for additive manufacturing. The theoretical part of the thesis includes an introduction to the basics of topological optimization as a design method, including its mathematical basis, and a description of the necessary steps that are an integral part of the optimization process. Also, a basic overview of the role topological optimization has in the process of designing a product intended for additive manufacturing is given. The practical part of the thesis provides an insight into the process of topological optimization of the carrier using the commercial software package Altair Inspire 2021.2.1. The carrier is optimized with the aim of mass reduction and is loaded with static loads whose values and orientation are described in the paper. Based on the obtained design, the necessary corrections were made within the program to eliminate sharp edges that could act as stress concentrators, and the aesthetics of the product itself was shaped. At the end of the paper, a conclusion was given on what was achieved by topological optimization of the structural part, and possible future improvements were proposed.