stop the transport track 13 and to divert the empty tubes 36 to the transport track 12 by means of the shunt formed by the electromagnet 11 the control to the remnant yarn detector 33 is then switched to maintain the electromagnet energized continuously in addition after each empty tube 36 has moved past the detector 33 it activates another electromagnet 37 causing the empty tube 36 to be returned over the transport path 14 for empty tubes to the delivery track 2 instead of being directed to the preparation device 15 regardless of this remnant cops 9 detected by the remnant yarn detector 33 can still be directed to the yarn end preparation device 15 by the selective nonactivation of the electromagnet 37 by the remnant yarn detector 33 after it has identified a remnant cop tubes with small quantities of remnant yarn may also be delivered to the yarn cleaner 10 in the manner described thus all the necessary functions of these devices occur even if the empty tubes 36 are circulating in the transport system at the various branching points from the delivery track 2 to the preparation segments 25 sensors 29 are provided which recognize arriving empty tubes 36 and open an adjacent shunt 30 to cause each caddy 4 carrying an empty tube 36 to continue traveling on the delivery track 2 which assures that the empty tubes will remain on the transport paths intended for them regardless of this operation the shunts 30 also serve to distribute the cops among the differing preparation segments 25 during normal operation of the bobbin.