Applying Operations Research techniques to planning of train shunting

In this paper, we discuss a model-based algorithmic approach for supporting planners in the creation of shunt plans for passenger trains. The approach provides an example of a mathematical model and a corresponding solution approach for model based support. We introduce a four-step solution approach and we discuss how the planners are supported by this approach. Finally, we present computational results for these steps and give some suggestions for further research.A* search;railway optimization;real world application;routing

Applying Operations Research techniques to planning of train shunting

In this paper, we discuss a model-based algorithmic approach for supporting planners in the creation of shunt plans for passenger trains. The approach provides an example of a mathematical model and a corresponding solution approach for model based support. We introduce a four-step solution approach and we discuss how the planners are supported by this approach. Finally, we present computational results for these steps and give some suggestions for further research

Shunting of Passenger Train Units: an Integrated Approach

In this paper, we describe a new model for the Train Unit Shunting Problem. This model is capable of solving the matching and parking subproblems in an integrated manner, usually requiring a reasonable amount of computation time for generating acceptable solutions. Furthermore, the model incorporates complicating details from practice, such as trains composed of several train units and tracks that can be approached from two sides. Computation times are reduced by introducing the concept of virtual shunt tracks. Computational results are presented for real-life cases of NS Reizigers, the main Dutch passenger railway operator.Optimization;Passenger Railways;Shunting

Port Rail Shunting Optimization Problems

openThe work focuses on a particular section of the intermodal chain of freight transportation, which is the link between rail and sea transportation modes and happens in the maritime port area. Among this field, the study deals with the management of rail operations, called here rail shunting operations, that have to be performed in the port area. Two optimization problems arises in this context. The first concerns the scheduling of the rail shunting operations, here called Port Rail Shunting Scheduling Problem (PRSSP). The second deals with the re-scheduling of the same operations in case of unpredictable events, here called Port Rail Shunting Re-Scheduling Problem (PRSRP). After a literature overview on the concerning studies, we concentrate on an innovative way to use the well known space-time networks as solution approach structure for both the above mentioned problems. The innovative structure has been called operation-time-space network and is deeply analyzed in a dedicated chapter. A network flow model based on an operation-time-space network for solving PRSSP has been developed. It has been tested using random generated instances providing good results. The same model has been extended in order to solve PRSRP and it has been tested giving good results as well. Finally, the models have been used to solve the real case of a port area located in Italy in order to test the applicability of the developed models to a real context. The tests have been executed using real data and provided good results confirming the possibility to apply the proposed approach in similar real problems.openXXXIII CICLO - LOGISTICA E TRASPORTIAsta, Veronic

Freight and passenger railway optimization

Das Ziel dieser Arbeit war es, einen Überblick über die aktuellen Beiträge der Literatur in den Bereichen der Eisenbahnlogistik sowohl im Güter- als auch im Personenverkehr zu geben. Während sich der Güterverkehr mit Problemen der Zusammenstellung der Züge und Waggons beziehungsweise der Verteilung der Leerfahrzeuge auseinander setzte, beschäftigte sich die Eisenbahnlogistik im Bereich des Personenverkehrs mit Optimierungsmodellen bezüglich Eisenbahnlinienplanung, Erstellung eines Fahrplanes, Inbetriebnahme von Fahrzeugen und Besatzungs- und Einsatzplanung. Die Bereiche der Eisenbahnlogistik haben in der Literatur eindeutig an Aufmerksamkeit gewonnen. In der Folge war es schwierig eine Auswahl aus dieser Vielfalt an Beiträgen zu treffen. Deshalb versucht diese Arbeit nur einen kurzen Einblick über einige wichtige Beiträge der letzten Jahre im Bereich der Eisenbahnlogistik zu geben. Aufgrund hochentwickelter mathematischer Techniken und deren Lösungsmöglichkeiten, die in den letzten Jahren aufgekommen sind, war es nun möglich die komplizierten Modelle der Eisenbahnlogistik in einer vernünftigen Zeit zu lösen. Darüber hinaus wurde ein Trend zur Entwicklung effizienterer entscheidungsunterstützender Hilfsprogramme für reale Gegebenheiten der Eisenbahnlogistik beobachtet. Im Großen und Ganzen sollten in Zukunft stärker integrierte Modelle der Eisenbahnplanung und Routenplanung entwickelt werden um robuste Lösungen und Methoden zu fördern.The aim of this work was to provide a survey of recent contributions about freight and passenger transportation. Whereas passenger optimization models considered problems such as line planning, train timetabling, platforming, rolling stock circulation, shunting and crew scheduling, freight transportation dealt with issues concerning car blocking, train makeup, routing, and empty car distribution. The field of rail transportation has clearly received attention resulting in a diversity of literature contribution. As it was difficult to handle the large amount of papers, this work is trying to give a short review of some important contributions made in recent years. Due to the increase in more sophisticated mathematical techniques, constant refinements in development of the models were made that were able to deal with larger problems. In addition, a trend towards more efficient transportation support systems was observed taking robustness into account. In addition, solution approaches that can deal with larger disturbances of the rail environment in a considerable speed and time, have received attention. Thus, future research can be done to develop more integrated models of scheduling and routing problems of train and passenger transportation to provide robust solutions and problem solving methods that handle disturbances of rail environment

Mathematical programming models to design and analyse efficient and robust raiway freight transport networks

(English) Searching to achieve an ambitious reduction in greenhouse gas emissions, the European Union has set as a goal a modal shift in freight transport of 30\% by rail or waterborne for the near future. The increasing efforts of many governments to intensify rail freight transport often must face the difficulties involved in improving both infrastructure and rail operations. Moreover, infrastructure management and business operations usually correspond to different entities with highly contradictory economic interests. Making progress on the reliability of the railway network is one of the main factors to be considered to make the use of the train more attractive as a means of transport for industry. Also, focusing on shippers' response to road and rail competition and the role of different rail undertakings competing with each other may help boost the use of rail for freight transport. Seeking to reinforce these two goals, this thesis introduces two independent mathematical optimisation models, which may also be complementary, and which have been developed under a common conceptual framework of data structures and variables to guarantee their compatibility. The first model is a mathematical programming-based design model for evaluating the impact on a mixed railway network from proposals for infrastructure improvement and capacity expansion that are oriented mainly toward increasing freight transportation. The model has been applied to extend elements of an existing mixed railway network, perform relatively less costly actions on the network, and enhance capacity by adding new blocking/control systems at specific locations. These aspects are usually not considered in models for regional planning. Rather than a model whose sole focus is on railway capacity expansion, this approach combines capacity-expansion with network design. Because the way investments generate returns to the freight transportation system is of utmost relevance for these types of problems, this model is based on the efficient frontier between investment and operating costs. The second model is a combined model for jointly evaluating the modal split road-rail, and the resulting railway freight flows on the railway network. This combined modal split-traffic assignment model is addressed to the case when a modal split based on a random utility model is available, and some of its coefficients may present a non-negligible variability. To this end, after the initial deterministic formulation, a robust counterpart of the model is developed. The model, formulated as a non-linear integer programming problem, is oriented to a multi-carrier environment and includes constraints to consider the interactions between the different types of flows on the railway network, allowing a detailed evaluation of the cost types of the carriers and the network capacity. An algorithmic solution based on the outer approximation method is shown to provide accurate solutions in a reasonable computational time for the robust and non-robust versions of the model. Examples centred on a section of the Trans-European Transport Network, the TEN-T Core network corridors, are reported to test the applicability of the models. Results show the effectiveness of both models. The design model can be a helpful tool for analysing the impact infrastructure investments may have on operating costs, where (implicit) capacity limitations in the scenarios to be evaluated may necessarily be taken into account. At the same time, it can be complemented with the combined modal split-traffic assignment model by assessing the possible shippers' response to the different railway carriers' services competing with each other and the road.(Español) Tratando de lograr una significativa y ambiciosa reducción de las emisiones de gases de efecto invernadero, la Unión Europea se ha marcado como objetivo que los modos de transporte de mercancías alternativos a la carretera, como el ferrocarril o la navegación fluvial, alcancen una cuota del 30% sobre el total de mercancías transportadas por tierra en Europa en los próximos años. Los crecientes esfuerzos que llevan a cabo los diferentes gobiernos se enfrentan con demasiada frecuencia con las dificultades que suponen mejorar de forma simultánea infraestructura y operaciones ferroviarias, habitualmente gestionados por entes diferentes con intereses económicos enfrentados. Mejorar la fiabilidad de la red ferroviaria es uno de los principales factores a tener en cuenta para hacer más atractivo el uso del tren como medio de transporte para la industria. Por otro lado, centrarse en los criterios que pueden llevar a las empresas a elegir entre carretera o tren, y en el papel que juegan las diferentes compañías ferroviarias en esta elección, compitiendo entre sí, puede ayudar a incrementar el uso del tren para el transporte de mercancías. Con la idea de reforzar estos dos objetivos, este trabajo de tesis presenta dos modelos matemáticos de optimización, independientes pero a la vez complementarios, y desarrollados bajo un marco conceptual de estructuras de datos y variables común para garantizar su compatibilidad. El primer modelo es un modelo de diseño basado en programación matemática para evaluar el impacto que pueden tener, sobre una red ferroviaria de uso mixto, propuestas de mejora de la infraestructura y de ampliación de la capacidad dirigidas principalmente a incrementar el uso del tren para el transporte de mercancías. El modelo se ha orientado a la modificación de elementos de una red ferroviaria de uso mixto existente, proponiendo intervenciones en la red relativamente poco costosas, y aumentando la capacidad añadiendo nuevos sistemas de bloqueo y control en ubicaciones específicas. Para este tipo de problemas, es de la máxima relevancia la manera en que las inversiones generan retornos al sistema de transporte ferroviario. Por eso, este modelo está basado en el óptimo equilibrio entre la inversión y los costes de operación. El segundo modelo es un modelo combinado para evaluar de forma conjunta el reparto modal entre carretera y tren, y los flujos de mercancías en la red ferroviaria resultantes. Este modelo está enfocado hacia aquellas situaciones en que hay un modelo de utilidad aleatoria disponible, pero algunos de sus coeficientes pueden presentar una variabilidad que no debe ser ignorada. Con esta finalidad, tras la formulación inicial del modelo determinístico se presenta una versión robusta de la formulación. El modelo, formulado como un problema de programación no lineal entera, está enfocado hacia un entorno en el que conviven (y compiten) diferentes compañías ferroviarias. Se detalla un algoritmo para resolver el modelo, basado en el método de aproximaciones externas, que permite obtener soluciones precisas con un tiempo computacional razonable, tanto para la versión determinística como para la versión robusta. Ejemplos basados en una sección de la Red Trans-Europea de Transporte (TEN-T por sus siglas en inglés) permiten validar la aplicabilidad y eficacia de los modelos. El modelo de diseño puede ser una herramienta útil para analizar el impacto que las inversiones en infraestructura pueden tener en los costes de operación, teniendo en cuenta las limitaciones de capacidad que existen en los escenarios evaluados. De la misma forma, se puede complementar este análisis con el modelo combinado de reparto modal y asignación de flujos, en el que se puede comprobar la posible respuesta de las empresas que requieren transportar sus productos ante los diferentes servicios ofrecidos por las compañías ferroviarias compitiendo entre si, y compitiendo con la carretera.Estadística i investigació operativ