An assembly line system comprises a plurality of cassette-type tooling elements and a plurality of moveable base modules. The tooling elements and the base modules have complementary mounting structures for supporting detachable mounting of the tooling elements onto the base modules. A driving system drives each base module to a respective first position within a product assembly area for the assembling a first product, and drives each base module to a respective second position within the product assembly area for assembling a second product. When the first product is dimensionally different than the second product, the respective first position is different than the respective second position for at least one of the plurality of base modules.