The planning and design of an inland container terminal is a complex task due to many interrelated design parameters and interdependent stakeholders. Design tools may support the optimization of technical, economic and logistical values, but this optimization is strongly inhibited by conflicting interests, political and environmental boundaries and strategic stakeholder behavior. The main research question in this contribution is: how can visualization-simulation tools be used in an early stage of complex inter-organizational decision-making on infrastructures in such a way that it enhances the quality and progress of this decision-making? A collaborative design environment was developed for the early phase of inter-organizational decision-making. In the gaming-simulation 'containers a drift', a number of public and private stakeholders try to reach initial agreement on an inland container terminal. A team of process-managers facilitate a collaborative design process and set up a number of ground rules for negotiation. A visualization-simulation tool is used to explore the various technical, economic, political and spatial issues. While negotiating on issues such as location and size of the terminal, small groups of stakeholders interactively draw several terminal layouts. Logistical and economic data, e.g., on ships, containers and costs are entered in a database. The terminal's performance and its dynamic behavior is simulated and assessed. The game was played in three sessions with a total number of 77 students. The evaluation results indicate that the various tools are easy to work with, greatly contribute to the quality and process of negotiation and generate mutual understanding.