There are two types of schedules, timetable schedules and service schedules.
Timetable schedules are used in conjunction with TT&TO rules, they are listed on the schedule pages of the timetable and convey authority for a train to operate. Trains listed in the schedule pages are regular trains. For each train, at some stations, a time or times will be listed. If there is only one time, it is the departure time, if two times are listed it is the arrival and departure times. A regular train cannot depart prior to its scheduled departure time.
Service schedules use much of the same language as timetable schedules but they do not convey authority on the main track. They are used to sell service to the customers, to measure performance and to estimate train movements. Service schedule may include additional information timetable schedules do not. Service schedules may describe blocking, connections, cutoffs, power requirements or other requirements of a train.