Abstract: A mounting system enables modular accessories to be fastened to any flat surface. Multiple, parallel accessory rails are mounted in parallel to provide a mounting system over substantially all of the area of a flat surface. The rails are spaced apart by channels to allow inverted rails to be inserted between and fastened to the parallel rails to expand the mounting capabilities of the mounting system. Removable attachment devices are engagable with the channels and the rails of the enclosure to expand the interconnection capabilities of the enclosure.