This Knowledge Document explains what happens when the CA 7 Trailer Queue reaches 100% Full for CA 7 r11.3 and earlier releases only.
If the Trailer Queue fills up, jobs will come into the queue in SKELETON status, unable to attach the JCL. The trailer queue contains JCL, job scheduling information such as job requirements or data set dependencies, Runlog data (see the LRLOG command), and PRIOR RUN JCL if RETAIN-JCL: Y is specified on the DB.1 screen. If this problem is encountered frequently you should consider increasing the size of the Trailer Queue. Below are the steps needed to allocate a new, larger trailer queue.