1,720,968 research outputs found
Improving Punctuality and Transfer Reliability by Railway Timetable Optimization
No full textThe Dutch railway network is operated close to capacity with the current safety system. This leaves little space for control by process operators by which a delayed train can cause severe delay propagation. The NS currently invest a large amount in punctuality improvement of the railway operations. This paper shows how the effect of delays can already be incorporated in the timetable design process to obtain robust and optimized timetables for a punctual and reliable operation. A detailed modelling approach is presented to compute periodic network timetables with an optimal distribution of buffer times at those points where they are needed the most without being too conservative. The variables are the buffer times and the proposed objective is to minimize a weighted sum of individual costs for each buffer time. Here, the weights define the relative importance of the buffer time costs. The following cost functions are proposed and proved to be convex for general running time distributions: buffer time (fast travel times for through passengers and small operating costs); expected delay due to buffer time failure of rolling-stock and crew connections (increasing punctuality) and train circulations (stability of train circulations); and expected transfer waiting time (trade-off between small transfer times and transfer reliability). The constraints on a feasible timetable are modelled conveniently by time window constraints concerning interactions between two periodic events (arrivals and departures). This is compatible with the timetable design system DONS of the NS. For the optimization problem these constraints are reformulated using the buffer times as variables rather than the periodic event times. The resulting cycle constraints state that the oriented sum of process and buffer times on fundamental cycles of the constraint graph is a multiple of the cycle time. The buffer times are not periodic by which they can be used straightforwardly in the objective functions. The periodic time windows are thus replaced by periodic cycles.Transport & PlanningCivil Engineering and Geoscience
WP5: Operations management of large scale disruptions
No full textTransport & PlanningCivil Engineering and Geoscience
Robuust spoor met ERTMS
No full textEen systeem is robuust als het blijft presteren bij incorrecte invoer of onder bijzondere condities. Een spoorsysteem is dus robuust als het blijft functioneren bij afwijkende procestijden ten opzichte van de planning, bij afwijkende beschikbaarheid van de infrastructuur, of bij slechte weersomstandigheden. Een betrouwbaar en robuust spoorsysteem kan worden verkregen door enerzijds het voorkomen van afwijkingen en storingen, en anderzijds het beheersen van de gevolgen van afwijkingen en storingen. Een technisch of menselijk systeem zal nooit 100% betrouwbaar zijn en daarom is beheersing van de gevolgen van een storing essentieel. Bij een robuust systeem wordt in het ontwerp al rekening gehouden met mogelijke afwijkingen en storingen in de onderliggende processen en componenten. De robuustheid van een spoorsysteem wordt bepaald door een integrale samenhang van infrastructuurontwerp, dienstregelingsontwerp, verkeersleiding en vervoerdersprocessen. Landelijke invoering van ERTMS kan een verbetering betekenen op veel meer terreinen dan alleen de treinbeveiliging en in het bijzonder biedt het mogelijkheden tot minder storingen aan infrastructuur, lagere capaciteitsbelasting en daarmee robuustere dienstregelingen, betere monitoring en bijstuurmogelijkheden van treinen bij vertragingen en verstoringen, en betere actuele machinisteninformatie in de treinen. Uitgangspunt is daarbij flexibiliteit van de infrastructuur en bijsturing met beslisingsondersteuning om effectief om te gaan met verstoringen. ERTMS Level 2 biedt de noodzakelijke continue tweezijdige datacommunicatie tussen trein en verkeersleiding waarmee een innovatiesprong op het spoor mogelijk wordt. Een landelijke migratie naar ERTMS biedt mogelijkheden tot innovatie, maar deze moeten nog wel vertaald worden naar een duurzame visie waarbij ERTMS het uitgangspunt vormt in plaats van de huidige beveiliging. Met name is een nieuwe visie nodig op robuust infrastructuurontwerp en een verkeersleiding die optimaal gebruik maakt van de geavanceerde communicatiemogelijkheden die met name ERTMS Level 2 biedt. Deze bijdrage geeft een voorzet tot een dergelijke visie die moet leiden tot een robuust spoorsysteem. Een wisselstoring leidt dan niet meer tot chaos op het hele spoor en bij verwachte slechte weersomstandigheden kunnen treinen gewoon blijven doorrijden zonder preventief aangepaste dienstregelingen met gehalveerde treindiensten.Transport and PlanningCivil Engineering and Geoscience
Stabiliteitsanalyse van spoorwegdienstregelingen
No full textDe capaciteitsverdeling van het spoor aan de diverse vervoerders gebeurt via basisuurpatronen (BUP’s) zoals vastgelegd in de Netverklaring door ProRail. De TU Delft heeft de analysetool PETER ontwikkeld waarmee de stabiliteit van basisuurpatronen op netwerkniveau kunnen worden geanalyseerd op een transparante, non-discriminatoire, controleerbare en reproduceerbare manier. PETER (Performance Evaluation of Timed Events in Railways) gaat uit van de basisuurpatronen voor alle treinseries op het hoofdnetwerk en regionale lijnen inclusief reizigersaansluitingen, materieelkeringen en infrastructuurbeperkingen zoals opvolg- en overkruistijden. Door deze stabiliteitsanalyse mee te nemen in het capaciteitsverdelingsproces kan de stabiliteit van basisuurpatronen worden getoetst met betrekking tot netwerkafhankelijkheden en bijvoorbeeld het uitbuigen van dienstregelingspaden in het dienstregelingsontwerpproces. Aan de hand van een case-studie voor het basisuurpatroon 2007 wordt de methodiek toegelicht.Transport and PlanningCivil Engineering and Geoscience
Optimal Train Dispatching at Railway Stations: A Discrete Event Dynamic System Approach
No full textReliability of transfers in a transportation network largely influences the level of service of trip chains. Especially in low-frequency service networks like (long-distance) railway networks. Running and dwell times are typically subject to random variations resulting in arrival delays during operation. If a scheduled transfer connection is endangered, process operators can decide to secure the tansfer by holding the connecting train until the passengers of the delayed feeder train(s) have arrived. However, a large departure delay may result in severe delay propagation. The effect of dispatching is thus very complex and can not be foreseen without advanced mathematical models. This paper proposes a mathematical model for computing optimal train waiting times depending on the actual state of delays in the train service network. The optimal strategy determines the transfers that must be secured or cancelled with respect to estimated arrival delays. Several objectives may be pursued, including the minimization of total delay or the minimization of weighted passenger waiting time. The incorporated delay propagation model explores the compensating effect of recovery times to arrival delays and is modelled as a discrete event dynamic system (DEDS), and in particular as a max-plus linear system. The optimal train waiting time strategies can be computed offline for each scenario of arrival delays. The optimal strategies result in critical passage times at reference points about 10 minutes before the railway stations. If the actual passage time exceeds the relevant critical passage time then the associated connection at the railway station is cancelled. The results can be incorporated in a decision support system to assist process operators at railway stations or traffic operators at traffic control centra.Transport & PlanningCivil Engineering and Geoscience
Robuust conflictvrije dienstregelingen
No full textTransport & PlanningCivil Engineering and Geoscience
Punctuality of railway operations and timetable stability analysis
No full textReliability of railway operations becomes more and more demanding with increasing train traffic, which asks for stable and robust timetables capable of neutralizing deviations from scheduled time-distance paths and stabilizing delay propagation. Timetable performance evaluation is thus a crucial aspect in the railway timetable design process to guarantee and maintain reliability of operations. Feedback from realized railway operations is essential to evaluate the performance of the timetable in practice and to find and improve structural shortcomings in the timetable design. This thesis presents the developed software TNV-Prepare which recovers the infrastructure utilization of train traffic from train detection data of the safety and signalling systems based on daily records of the train describer systems, the so-called TNV-logfiles. A case-study at the Dutch railway station Eindhoven demonstrates the potential of a statistical analysis of this train traffic data to identify structural sources of delays. Railway operations are characterized by many network interdependencies resulting from the timetable and shared usage of railway infrastructure. Therefore, a railway timetable must be carefully tested on stability and robustness before implementation using a mathematical model of the scheduled railway operations. This thesis proposes an analytical model for evaluating timetable stability and robustness based on max-plus algebra. The max-plus linear system approach gives a formal stability test based on a max-plus eigenvalue problem, identifies critical events and processes, quantifies robustness in terms of recovery times, and computes the propagation of delays over time and space. The method has been implemented in the software PETER (Performance Evaluation of Timed Events in Railways) which enables users to analyse large-scale network timetables in real-time. A case-study of the Dutch national railway timetable illustrates the developed methodology.Civil Engineering and Geoscience
WP3: Development of robust and resilient tmetables
No full textTransport & PlanningCivil Engineering and Geoscience
Synchronization Control of Scheduled Train Services to Minimize Passenger Waiting Times
No full textDuring operation a transportation service may wait on delayed feeder services to secure scheduled transfers. For low-frequent connecting services this has a major positive impact on the transfer waiting times. However, the resulting synchronization control time of the connecting service also affects the waiting times of originating and through passengers on the current transfer station, as well as the waiting times on subsequent stations resulting from delay propagation in the service network. A systematic mathematical model has been developed to compute all affected waiting times of initial train departure delays. The delay propagation is modelled as a discrete event dynamic system, and in particular as a maxplus linear system. It explores the effect of buffer times to compensate for arrival delays. The model can be utilized to evaluate the optimal synchronization control policy with respect to given arrival delays: secure or dissolve a transfer. The objective is the minimization of the total relative (generalized) passenger waiting time. Another application is the analysis of existing buffer times on passenger waiting times in service network timetables.Transport and planningCivil Engineering and Geoscience
On-time real-time traffic management of minor perturbations
No full textTransport & PlanningCivil Engineering and Geoscience
- …
