Application of a Hybrid Algorithm Based on Quantum Annealing to Solve a Metropolitan Scale Railway Dispatching Problem

We address the applicability of quantum-classical hybrid solvers for practical railway dispatching/conflict management problems, with a demonstration on real-life metropolitan-scale network traffic. The railway network includes both single-and double segments and covers all the requirements posed by the operator of the network. We build a linear integer model for the problem and solve it with D-Wave's quantum-classical hybrid solver as well as with CPLEX for comparison. The computational results demonstrate the readiness for application and benefits of quantum-classical hybrid solvers in the a realistic railway scenario: they yield acceptable solutions on time; a critical requirement in a dispatching situation. Though they are heuristic they offer a valid alternative and outperform classical solvers in some cases

Integrated capacity assessment and timetabling models for dense railway networks

Mainline railways in Europe are experiencing increasing use as the worldwide demand for passenger and freight transport is growing across all transport modes. At the same time, much of the existing railway network is reaching its capacity and has become susceptible to disturbances. This thesis creates, optimizes, and evaluates railway timetables to promote more reliable, attractive and sustainable railway transport systems. In essence, we demonstrate that optimization, simulation and data analysis can be successfully applied to improving railway traffic planning and account for better infrastructure capacity use and increased level of service for passengers and freight operators.TRAIL Thesis Series no. T2017/9, the Netherlands TRAIL Research SchoolTransport and Plannin

Resilience in railway transport systems: a literature review and research agenda

Critical infrastructure networks, such as transport and power networks, are essential for the functioning of a society and economy. The rising transport demand increases the congestion in railway networks and thus they become more interdependent and more complex to operate. Also, an increasing number of disruptions due to system failures as well as climate changes can be expected in the future. As a consequence, many trains are cancelled and excessively delayed, and thus, many passengers are not reaching their destinations which compromises customers need for mobility. Currently, there is a rising need to quantify impacts of disruptions and the evolution of system performance. This review paper aims to set-up a field-specific definition of resilience in railway transport and gives a comprehensive, up-to-date review of railway resilience papers. The focus is on quantitative approaches. The review analyses peer-reviewed papers in Web of Science and Scopus from January 2008 to August 2019. The results show a steady increase of the number of published papers in recent years. The review classifies resilience metrics and approaches. It has been recognised that system-based metrics tend to better capture effects on transport services and transport demand. Also, mathematical optimization shows a great potential to assess and improve resilience of railway systems. Alternatively, data-driven approaches could be potentially used for detailed ex-post analysis of past disruptions. Finally, several rising future scientific topics are identified, spanning from learning from historical data, to considering interdependent critical systems and community resilience. Practitioners can also benefit from the review to understand a common terminology, recognise possible applications for assessing and designing resilient railway transport systems.Transport and Plannin

Scheduling multimodal alternative services for managing infrastructure maintenance possessions in railway networks

Highly utilized railway networks require regular infrastructure maintenance. Different track sections often need to be closed for entire days to carry out engineering works, which makes the regular timetables no longer feasible and thus adjusted railway services and temporary alternative services need to be planned. We introduce the Multimodal Alternative Services for Possessions (MASP) problem to support the planning of alternative services, from the passenger and transport operator points of view, including an adjusted train timetable, bus-bridging services and extra train services. The MASP problem is formulated based on the Service Network Design Problem and the Vehicle Routing Problem. To solve it efficiently, we develop a solution framework that incorporates heuristics based on the column and row generation with mixed-integer linear programming. The developed framework provides the optimized alternative service routes, schedules and passenger flows routing. We demonstrated the performance of the MASP solution framework on the real-life Dutch railway network. The results show that the MASP framework is capable of efficiently generating alternative services to route passenger flows affected by possessions with a very limited increase in the total passenger costs compared to a scenario with no link closures. High computational efficiency is observed even for highly disrupted networks.ISSN:0191-2615ISSN:1879-236

Estimating impacts of covid19 on transport capacity in railway networks

Due to the covid19 crisis, public transport (PT) systems are facing new challenges. Regarding restrictive measures such as physical distancing and the successive returning of passengers after the “intelligent lockdown”, significant lack of transport capacity can be expected. In this paper, the transport capacity of a PT network is assessed, using a mathematical passenger route choice and train scheduling model. By analysing the overall number of transported passengers and the resulting link and train utilization; the networks capabilities of facilitating different demands under capacity restrictions (e.g. physical distancing) are addressed. The analysis is performed on the Dutch railway network. The results show that at most 50% of the pre-covid19 demand can be transported, while most of the trains will be highly utilized reaching their maximum occupation. Thus, significantly more parts of the network are becoming highly utilized, leading to a more congested and vulnerable system than in normal conditions before covid19.Transport and Plannin