"Q" Paths are those that run only when required. By default, TRUST assumes such trains are not running, as they are not automatically "called" (activated in RTT speak). Manual calling of such a schedule makes it live in TRUST and enables reporting to take place.
"Y" Paths are the same, in that they are manual call, but exist where there are different versions of a train. This is usually, but not exclusively, because of different origin and/or destination points, but sharing a common core path. For example, there used to be coal trains from various Scottish coal loading points to multiple powers stations in West Yorkshire, which would share a common path between Carlisle and Leeds. The one that was required on any given day would be manually called.
Section 5 possessions are cyclical possession opportunities on midweek nights. In my area, many of these are every six weeks. Unlike Section 4, the timetable is not built around Section 5 possession opportunities and train schedules need to be amended on a weekly basis to fit around them. There are also Section 7 possessions (this is known as "The Register"), which are jobs that are too time consuming to be accommodated in Section 4 or Section 5 opportunities.
