Early today there was an incident at the high school, large groups of kids not listening and getting out of control. So, the PD unit assigned to the high school called in a couple more units, which were dispatched and on their way. Then that same PD unit called for the pipeline units to come, and then the pipeline cars were dispatched. I am curious as to what exactly is the pipeline cars/units. I have never heard this term used before, and was wondering if any of you knew what they are.