forward that information to a control unit 11 fig1 shows an embodiment of the tray feeder 3 in an embodiment with a first train chain 12 a and a second train chain 12 b which each comprise two transport chains 13 a 13 b each transport chain 13 a and 13 b having three pusher elements 14 a and 14 b respectively attached as shown more specifically the first train chain 12 a may comprise two transport chains 13 a wherein one transport chain 13 a is arranged on the right and one transport chain 13 a is arranged on the left of a track s upon which the trays 8 are conveyed along the tray feeder 3 these two transport chains 13 a are connected with each other by pusher elements 14 a which span therebetween the three pusher elements 14 a define a section of the first train chain 12 a the section of the first train chain 12 a being designed to collect and to transport a train i e a group of three trays 8 similarly as shown in fig1 the second train chain 12 b comprises two transport chains 13 b wherein one transport chain 13 b is arranged on the right and one transport chain 13 b is arranged on the left of the track s upon which the trays 8 are conveyed along the tray feeder 3 these two transport chains 13 b of the second train chain 12 b are connected with each other by three pusher elements 14 b the three pusher elements 14 b define a section of the second train chain 12 b which can collect and transport a train i e a group of in this case three trays the two train chains 12 a 12 b.