1,721,042 research outputs found
Existing and future applicable approaches on railway traffic control from an agent-based perspective
No full textAssessment of advanced dispatching measures for recovering disrupted railway traffic situations
No full textISSN:0361-1981ISSN:2169-4052ISSN:2169-405
Reordering and Local Rerouting Strategies to Manage Train Traffic in Real Time
No full textTraffic controllers regulate railway traffic by sequencing train movements and setting routes with the aim of ensuring smooth train behaviour and limiting, as much as possible, train delays. In this paper, we describe the implementation of a real-time traffic management system, called ROMA (Railway traffic Optimization by Means of Alternative graphs), to support controllers in the everyday task of managing disturbances. We make use of a branch-and-bound algorithm for sequencing train movements, while a local search algorithm is developed for rerouting optimization purposes. The compound problem of routing and sequencing trains is approached iteratively, computing an optimal train sequencing for given train routes and then improving this solution by locally rerouting some trains. An extensive computational study is carried out, based on a dispatching area of the Dutch railway network. We study practical size instances, and include in the model important operational constraints, including rolling stock and passenger connections. Different types of disturbances are analysed, including train delays and blocked tracks. Comparison with common dispatching practice shows the high potential of the system as an effective support tool to improve punctuality
Optimal inter-area coordination of train rescheduling decisions
No full textRailway dispatchers reschedule trains in real-time in order to limit the propagation of disturbances and to regulate traffic in their respective dispatching areas by minimizing the deviation from the off-line timetable. However, the decisions taken in one area may influence the quality and even the feasibility of train schedules in the other areas. Regional control centers coordinate the dispatchers’ work for multiple areas in order to regulate traffic at the global level and to avoid situations of global infeasibility. Differently from the dispatcher problem, the coordination activity of regional control centers is still underinvestigated, even if this activity is a key factor for effective traffic management. This paper studies the problem of coordinating several dispatchers with the objective of driving their behavior towards globally optimal solutions. With our model, a coordinator may impose constraints at the border of each dispatching area. Each dispatcher must then schedule trains in its area by producing a locally feasible solution compliant with the border constraints imposed by the coordinator. The problem faced by the coordinator is therefore a bilevel programming problem in which the variables controlled by the coordinator are the border constraints. We demonstrate that the coordinator problem can be solved to optimality with a branch and bound procedure. The coordination algorithm has been tested on a large real railway network in the Netherlands with busy traffic conditions. Our experimental results show that a proven optimal solution is frequently found for various network divisions within computation times compatible with real-time operations.Transport & PlanningCivil Engineering and Geoscience
Comparing the effectiveness of two real-time train rescheduling systems in case of perturbed traffic conditions
No full textWeather Effects on the Public Transport Ridership of the City of Zurich at a Stop-to-stop Level
No full textThis paper studies the influence of weather on the public transport (PT) ridership of the Swiss city of Zurich. The Zurich PT network is widely recognized as one of the best in the world; to continue guaranteeing its efficiency and attractiveness it is essential to cope with the weather conditions, which can induce a change in the travel demand that can negatively affect, if not taken into account, the performance of the transport network.This paper first introduces the considered sources of data and their behavior over time and space. It then investigates, by means of analytical and data science techniques, the spatio-temporal correlations of the selected weather parameters on the vehicle occupancy, which is chosen as ridership measure representative of the PT usage.Results show that rain affects significantly the PT ridership, and that the extent deeply depends on the time, the day type and the section location in the network. The spatial and temporal differences in the way weather affects the occupancy of the PT vehicles are among the major findings of this work, and could be used by the PT provider to adjust the service and optimally allocate the resources (i.e., tram types and compositions) depending on where and when they are more necessary
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