A modular drive system for a self-stacking conveyor belt adapted to travel at least along one non-linear path segment includes at least one drive cassette adapted to removably engage sidelinks on an edge of the conveyor belt, and preferably at least a first drive cassette engaging the conveyor belt sidelinks at an inner curve of the segment and at least a second drive cassette engaging the conveyor belt sidelinks at an outer curve of the segment.