The conveyor system features plural endless and independently powered conveyor chains traveling individual guide tracks, one chain and track representing a main power conveyor line traversing the entire length of the system, and one or more further and similar chain and track-type branch lines which, at spaced zones therealong, converge and diverge in relation to the main line, paralleling the latter through some length. Thus, pusher dogs on the parallel-traveling conveyor reaches may selectivel...