Abstract and figures The paper considers the problem of optimization of the box section of the main girder of the bridge crane with rail placed above vertical plate. Criteria of strength, local and lateral stability of the girder were applied as the constraint functions. In addition, an influence of production technology on obtained optimization results is shown through comparative analysis. Reduction of girder mass is set as the objective function and the method of Lagrange multipliers was used as the methodology. The comparative optimization results show changes of the box section optimum geometric values due to Euro code or domestic standard appliance. The significant recommendations for crane designers were made upon the comparative analysis of optimization results and existing solutions.