1.9.6 On the right lines: summing up
Timetables and distance-time graphs are different representations of scheduled train movements. They are both models which can be used to predict when trains will run, to analyse and compare different schedules when problems occur, and to design new operating schedules to meet new demands. Both models provide information which allows the company to operate safely and flexibly. The information is used by different groups of people:
by passengers to plan their trips;
by track staff to be aware of train movements;
by signalling staff to ensure the safety of trains travelling in opposite directions on the line;
by planning staff to schedule new or additional services.
Which model would be more useful to each of the above groups of people?
Passengers are likely to find timetables more useful. Signalling and track staff will probably find both helpful. The graph shows trains in both directions at once at intermediate spots, but the times at stations are easier to read from the table. Planning staff need graphs to be able to fit in a new service.