Timetables: Which Fits, How Long to Wait

A timetable is a grid, and the first skill is staying on one line of it. A row is one film: its name, its start, its end. Lost Map runs from twelve twenty to two ten, and that duration is the usual hop through landmarks, forty minutes to one, an hour to two, ten more, one hour fifty. Keep a finger on the row, because the classic slip is reading the start of one film with the end of the film below it.

How long to wait means finding the first departure after the time you arrive, and subtracting. Reach the stop at seven thirty and the seven twenty-five has gone; the next is seven forty-five, a fifteen-minute wait. Arrive one minute after a bus and you wait almost the whole gap. If the buses run every twenty minutes, you can extend the timetable yourself: after eight oh five comes eight twenty-five. And once you are on the bus, the journey time is added to the departure, not to when you arrived at the stop.

A train timetable lists stops across and trains down. The time between two stops is the difference of the two entries on that train's row: Central eight twelve to Strathfield eight twenty-four is twelve minutes, and Central to Penrith is fifty-eight. Adding the legs gives the same fifty-eight, and if the two methods disagree you misread a cell. If you must be somewhere by nine and the train arrives at nine ten, it is the wrong train by ten minutes; look for an earlier row.

Which film can you see from start to finish between a drop-off and a pick-up? Two checks, and both must pass: it starts after the drop-off, and it ends before the pick-up. Dropped at twelve and collected at two thirty, Lost Map is the only one: Robot Kids starts in time but runs five minutes past the pick-up, and Deep Blue ends in time but had already started. Then the small questions: the wait before it starts, twenty minutes, and the spare time after, another twenty.

Every timetable question is find the right cell, then hop. The wait is the next departure minus your arrival. The arrival is the departure plus the journey. Home by four thirty with a twenty-minute walk: Star Trail ends at four oh five, the walk gets you home at four twenty-five, five minutes to spare. A train that arrives at nine ten when you needed nine is ten minutes late. Quiz and exercises now.