This paper deals with the modelling of a particular class of manufacturing lines, governed by a rule imposing the self-balancing. Bucket brigades were first studied as stochastic dynamic systems. Thus, a sufficient condition for self-balancing was proved. Under some particular conditions, bucket brigades may be regarded as nonlinear dynamic systems. Simulations have shown that their state trajectories are piecewise continuous in between occurrences of certain discrete events. Bucket brigades may therefore be modelled as hybrid dynamic systems, more precisely, with autonomous switching and autonomous jumps. A stability analysis is possible in the frame of hybrid dynamic systems with discontinuous motions.