Abstract: Mechanized mail sorting offices require packets to be sorted according to destination into one of many bags. A typical mechanized system includes a loading mechanism for transferring packets from stationary input pockets onto a continuously moving sequence of containers which pass all destinations in turn and unload as required. The system according to the invention consists of a number of separate self powered single trolleys (TL) which run on a tracking network. Each trolley (TL) is adapted to be programmed with the route to be taken to the destination of the packet(s) loaded into it. The trolley (TL) co-operates with en-route track-side signposts (TSB) enabling steering arrangements (SM) in the form of a guide arm at the front of the trolley (TL) to guide the trolley around the tracking network to and from its required destination for unloading its package into a bag.