To avoid road congestion, we are developing a highly automated underground transport system using automatic guided vehicles (AGVs) around Schiphol Airport. It is unique in its scale, incorporating 16 to 25 km tubes connecting five to 20 terminals, and it includes 200 to 400 AGVs to transport an estimated 3.5 million tons of cargo in 2020 with different ordering priorities. According to the current plans, the system will run from 2006 on. Since 1997, we have used object-oriented simulations to plan the dimensions of the system (number of AGVs, terminal sizes) and to design the layout (network, terminals). We showed that an investment reduction of plus or minus 20 percent is feasible using periodically switched one-way tube sections. We developed a variety of logistics optimization algorithms and heuristics, including allocating AGVs between terminals, scheduling terminals, and controlling traffic. We used simulation control structures to test prototype AGVs on a test site. Performing distributed simulations with a mixture of simulated and real objects, we could reduce the risks of the new technology.