A collation method and apparatus that is immune from singularization faults which disrupt the collation process. Each signature is loaded into individual grippers of a power and free gripper conveyor system. Those grippers that experience a miss or a double are diverted out of the process stream. Only those grippers that carry one and only one signature are allowed to continue on in the primary signature queue. The grippers that continue on in the primary signature queue are re-queued into a sequential order which eliminates gaps in the queue. The collation machine accepts signatures from the downstream end of the signature queue as the singularization process continues to add signatures to the upstream end of the signature queue. The singularizer uses a track and diverter structure, where grippers without a signature are diverted to the diverter structure and grippers with a signature continue on the track to a collator.