When a T/O posts during schoolcar, it's my understanding that they must post on each line and yard in their division (A or B.) Do T/Os have any specific "qualifications" for each line, and must they maintain them? Example, a T/O with some seniority on the "A" division picks a job on the . They work that job for 5 years. They then want to pick a job on the . Would they have to do any requalifying on the Jerome/Lexington/Eastern Parkway Lines? Also, if a T/O is working extra-extra, especially on the B division, how hard is it to keep all the territory straight?