A method and apparatus for joining at least one daughter cart to a mother cart utilize a coupling system having first and second coupling rails attached to one of the mother and daughter cart frames, and a third coupling rail attached to the other of the mother and daughter cart frames. The coupling rails all extend in a parallel manner to one another in a direction generally perpendicular to a primary transport direction and parallel the underlying surface, when engaged for conveying the daughter cart with the mother cart. The third coupling rail is retained in a channel between the first and second coupling rails, in such a manner that the daughter cart is coupled to and moves with the mother cart as the mother cart is moved in the primary transport direction while the third coupling rail is positioned in the channel between the first and second coupling rails.