The New Dutch Timetable: The O.R. Revolution

When it comes to commuting in Holland, travel by rail affects an enormous number of Dutch citizens. Netherlands Railways (NS) operates passenger trains on all the principal lines in the Netherlands, transporting approximately 1.1 million passengers daily. In this way, NS plays a very important role in the mobility of the Netherlands.

NS used operations research to produce for the entire country a completely new timetable, which has been in operation since December 2006. Since so many daily life patterns are changed through the modifications in the railway timetable, this change resulted in considerable media attention and in many discussions in the Dutch parliament. The last major change in the timetable took place in 1970. Since then, the number of passenger kilometers on the network nearly doubled, from 8.0 billion to 15.8 billion a year. To accommodate more passengers and at the same time reduce delays using the old timetable could only be realized if railway infrastructure were significantly extended. A report on the Dutch railway sector estimates that those investments would cost an additional €10 billion ($15 billion) through 2020. Because this costly expenditure was not considered acceptable, the only way for NS to accommodate more passengers was to develop a new timetable from scratch. 

This new timetable and the related resource schedules for rolling stock and crew have been constructed with the help of O.R. tools. The timetabling step itself consists of two main components: the generation of a cyclic timetable, which is repeated every hour, and the detailed routes through the different stations. To solve both components, two O.R. problem solvers were developed. Another O.R. solution approach was invented to construct rolling stock schedules. All these methods were developed in close cooperation with the scientific community (CWI and Erasmus University Rotterdam). The crew schedules were generated by TURNI, a software system from Double-Click.

The impact for NS is an additional annual profit of €40 million ($60 million) in 2007, with an expectation of growing to €70 million ($105 million) in the coming years. These benefits come from both more efficient resource schedules and an increase in passenger demand and punctuality. Lines with the greatest timetable improvements saw an increase in passenger demand of almost 15% in 2007. On-time performance—the percentage of trains arriving within three minutes of the scheduled arrival time—increased from 84.8% in 2006 to 87.0%, an all-time high record, in 2007. As a result, surveys show that there are more satisfied passengers than ever before. The CPB, an independent advisor of the Dutch government, conservatively estimates every percentage point increase in punctuality of the railway system to be worth €8 million ($12 million) a year for Dutch society. 

Since, in the future, additional railway transport can be accommodated by the new timetable, the growing demand for transportation to the main cities in the rush hours can be facilitated by railway transport. This helps reduce congestion on the roads into and inside these cities, as well as reduce greenhouse gases.