Topological optimization can be understood as a combination of shape and dimensional modification of the construction in order to find the optimal layout of the structure bounded by a predefined region, for a given set of loads, boundary conditions and constraints with maximizing system performance. In our case, we applied Density Based Method and Level Set Based Method to the design of a freight intermodal railway wagon, which is to be equipped with an automatic digital coupling. The wagon, for which the front part of undercarriage was modified on the basis of topological optimization, was subsequently subjected to a strength simulation analysis according to EN 12663-2 by the finite element method. By applying these optimization methods in the selected construction, we achieved savings on the total weight of the wagon of approximately 20%. This weight reduction can be even higher if we apply the mentioned procedures to the middle part of the wagon undercarriage.