A new methodology for taking into account of the cargo pendulum angle change at minimum operating radius of the gantry cranes level luffing jib systems is proposed. The impact of this change in electric motor power calculating has been studied. An optimization mathematical model that takes into account this change and the impact of node displacements on the design of the gantry cranes level luffing jib systems is built. Parameters, optimization criteria and their boundaries are determined. Optimization of the construction taking into account these factors was made using the Pareto optimization procedure and the results were compared with previous studies.