This paper discusses a large simulation model that was developed to aid the reconstruc tion efforts after a disastrous fire at Tinker Air Force Base. The model, developed in SLAM, facilitated the analysis and efficient design of the functional layout that replaced the previous machine-based layout in the appropriate number of machines to place within a modular repair center (MRC), stacker capacity for in-process inventory, location of elevators for sending parts to the conveyor, and the optimal design and routing scheme for overhead conveyor system. The new layout, as predicted by the simulation model, has proven to be quite effective compared with the pre fire layout. Improvements that have been achieved include a 50 to 80% decrease in material handling, substantive decrease in flow times, better manage ment control of part transfers, $4.3 million savings from the elimination of excess capacity, and $1.8 million savings resulting from higher direct labor efficiency.