Timetable 2007: Why and How?

1. Timetable 2007:Why and How? Dennis Huisman Econometric Institute & ECOPT, Erasmus Univ. RotterdamDept. of Logistics, NS www.ecopt.nl Thursday January 18, 2007

2. Schedule • Introduction on the Dutch railway system • Why a new timetable? • How is the 2007 timetable constructed? • Different steps • OR models • Process • Future developments

3. Some figures 1.100.000 passenger trips per workday 15.000.000.000 passenger kilometers per year • passenger trains per workday 300 cargo trains per workday 2800 kilometers of tracks 377 stations

4. 0 50km Dutch railway system Characteristics: • Dense railway system • Cyclic timetable (1 hr) • Several train types • High utilization of infra • Many connections

5. Timetable 2007: Why? • No major changes since “Spoorslag ’70” but much more passengers • Improving robustness of the system • New commercial product with high speed trains, Intercity services and sprinters (no semi-fast trains anymore) • Better connections with Belgium and Germany • New infrastructure would be available in 2007 (HSL, Betuweroute, quadrupling Amsterdam-Utrecht)

6. How to construct a new timetable? Three steps: • Make a line plan, i.e. determine the direct connections and the frequencies, etc. • Construct the timetable for one hour, i.e. decide on the exact arrival and departure times, connections, etc. • Construct the timetable for a whole week Strong dependency between the first two steps, and between these steps and rolling stock planning

7. Line planning (1) • Input: O-D matrix • Output: routes with their frequency & some transfers (e.g. 2/hr IC Den Helder – Amsterdam – Utrecht - Nijmegen, 2/hr IC Schagen/Alkmaar – Amsterdam – Utrecht – Eindhoven - Maastricht/Heerlen, 2/hr IC Schiphol – Utrecht - Eindhoven). • Possible criteria: • As much direct connections as possible • Robustness • Short travel times

9. Line planning (2) • Not many OR models are used in line planning • Decisions mainly made on properties of the infrastructure, market specifications and political wishes • Most discussions in public/media are about the line plan • Example: Voorburg, Zoetermeer, Gouda and Woerden all like to have an Intercity station on the route Utrecht – The Hague, on the other hand travel times from North & East to the Hague should be short.

10. Timetabling (1) • Determine for each train on all stations the exact arrival and departure times such that • headway constraints are satisfied, • transfers are as much as possible satisfied, • travel times (including buffers) have to be taken into account, • trains on the same line are equally distributed, • the timetable is cyclic.

11. Basic hour pattern Amersfoort – Lunteren - Ede-Wageningen

12. Timetabling (2) • The new timetable is constructed with DONS (= Designer Of Network Schedules) • DONS consists of a database, GUI and two solvers: CADANS and STATIONS • CADANS creates the ‘basis hour pattern’ and is developed by CWI (Schrijver & Steenbeek, 1994) • STATIONS creates the ‘basis platform assignment’ and is developed by Zwaneveld et al. (1996) • Both solvers are based on OR models

13. CADANS (1) • The OR model is based on the Periodic Event Scheduling Problem (PESP) • Examples of constraints with T: cycle time Q(e1,e2): binary decision variable indicating whether event e1 is carried out before event e2 or not

14. CADANS (2) with T: cycle time Q(e3,e4): binary decision variable indicating whether event e3 is carried out before event e4 or not • PESP is solved with preprocessing techniques, constraint propagation and local optimization techniques

15. CADANS (3) • CADANS provides either feasible solution or gives some indication why it is infeasible • In the latter case, planner should change the specifications and try again

16. Reliability of timetables • Measured by punctuality of the railway system • Simulation is used to determine the expected punctuality of a ‘basic hour pattern’ • This is done by introducing disturbances and measuring their effect on the overall punctuality • The new timetable is simulated with SIMONE (= SImulation MOdel of NEtworks) developed by ProRail and NS

17. Timetable 2007: process (1) • Focus: timetable 2009 • Timetable 2007 is derived from timetable 2009, but has the line plan of 2006 on some parts of the network (e.g. between Amsterdam and Vlissingen) • Joint work between NS, ProRail and Raillion • Start 2003

18. Timetable 2007: process (2) • 10 completely different line plans have been considered (including very extreme ones) • For all of them DONS generated a ‘basis hour pattern’ • SIMONE runs were done to measure the punctuality of the different timetables • Consequences on travel times/transfers/frequencies for all passengers in the O-D matrix have been determined • General statistics on expected number of passengers, costs and revenues have been calculated as well

19. Timetable 2007: process (3) • Board choose line plan in March 2005 (mix of 2 of the initial line plans) • Go/no go decision in December 2005 • Afterwards 1-hour timetable is copied to 7*24 hours and rolling stock and crew schedules are constructed • In the mean time: several small adjustments (e.g. shorter travel times to the North) and one large adjustment (not opening four tracks Amsterdam-Utrecht)

20. Future developments Running time supplements • Timetable 1970-2006: 7% running time supplement • Timetable 2007: 5% running time supplement • Vromans et al. (2005) developed an optimization model to distribute the supplements such that the average delays can be minimized • A practical experiment on the Zaanlijn with a modified timetable showed that the punctuality can be improved by a few percent points • Timetable 2009: practice ??

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