Maritime container terminals are playing a growing role within global transport chains. As intermodal nodes between sea traffic flows and inland distribution, they are very important to shipping lines. The current trend of moving towards economies of scale in regard to mother vessels is also having a tremendous impact on seaport operations and hinterland transportation in terms of 'call size'. This paper deals with the study of multimodal container flows at an Italian maritime terminal, focusing the attention on the performance of road and rail connections. In this framework, the current modal unbalance generates heavy problems of congestion and compromises the overall terminal competitiveness. This paper applies a discrete event simulation approach, in order to evaluate the feasibility of an alternative and more balanced scenario achievable in a short-mid-term perspective. Our goal is to enhance the performance of rail connections, without proposing the realisation of a new railway line which is only attainable in the long run, but trying to exploit to the full the available endowment of assets through a deep operational restructuring. Simulation runs performed in this perspective revealed the adequacy of such an approach and demonstrated the successful effects of a modal re-equilibrium.