I understand that the public timetable is the published times that the train was planned for. Until now I assumed the working timetable was the real time predictions of the service but the working times don't seem to change after the schedule has been published. Taking this example: http://uktra.in/rtt/train/201612287103042 the train was clearly running behind schedule but the working times remain unchanged. So what is the difference between public times and working times?