In time of fast globalization and urbanization, the volumes of transported containers have significantly increased in the last decades. The challenges of operating with high volumes of containers have propagated from the deep-sea terminals into the hinterland network resulting in extensive use of road transportation, long waiting times and high carbon emissions. Synchromodal transport has addressed these challenges by promoting integration of services and real-time decisioning to increase the overall flexibility of the system. However, little is known about the effects of applying flexible concepts on operational planning decisions and whether these decisions have reflection on the performance of the system when centrally taken. This paper proposes a research for a design of an operational strategy which supports operational decisions on container routing and mode choice among trucks and barges. Model Predictive Control planning approach is applied to optimize the simultaneous routing of containers, trucks, and barges. The effectiveness the proposed strategy is evaluated in the presences of increased container volumes and compared to a Benchmark strategy by the means of simulation experiments. The impact of implementing flexible decisions on system performance and realized operational costs is investigated.