13,448 research outputs found

    Scheduled service network design for integrated planning of rail freight transportation

    Get PDF
    Cette thĂšse Ă©tudie une approche intĂ©grant la gestion de l’horaire et la conception de rĂ©seaux de services pour le transport ferroviaire de marchandises. Le transport par rail s’articule autour d’une structure Ă  deux niveaux de consolidation oĂč l’affectation des wagons aux blocs ainsi que des blocs aux services reprĂ©sentent des dĂ©cisions qui complexifient grandement la gestion des opĂ©rations. Dans cette thĂšse, les deux processus de consolidation ainsi que l’horaire d’exploitation sont Ă©tudiĂ©s simultanĂ©ment. La rĂ©solution de ce problĂšme permet d’identifier un plan d’exploitation rentable comprenant les politiques de blocage, le routage et l’horaire des trains, de mĂȘme que l’habillage ainsi que l’affectation du traffic. Afin de dĂ©crire les diffĂ©rentes activitĂ©s ferroviaires au niveau tactique, nous Ă©tendons le rĂ©seau physique et construisons une structure de rĂ©seau espace-temps comprenant trois couches dans lequel la dimension liĂ©e au temps prend en considĂ©ration les impacts temporels sur les opĂ©rations. De plus, les opĂ©rations relatives aux trains, blocs et wagons sont dĂ©crites par diffĂ©rentes couches. Sur la base de cette structure de rĂ©seau, nous modĂ©lisons ce problĂšme de planification ferroviaire comme un problĂšme de conception de rĂ©seaux de services. Le modĂšle proposĂ© se formule comme un programme mathĂ©matique en variables mixtes. Ce dernie r s’avĂšre trĂšs difficile Ă  rĂ©soudre en raison de la grande taille des instances traitĂ©es et de sa complexitĂ© intrinsĂšque. Trois versions sont Ă©tudiĂ©es : le modĂšle simplifiĂ© (comprenant des services directs uniquement), le modĂšle complet (comprenant des services directs et multi-arrĂȘts), ainsi qu’un modĂšle complet Ă  trĂšs grande Ă©chelle. Plusieurs heuristiques sont dĂ©veloppĂ©es afin d’obtenir de bonnes solutions en des temps de calcul raisonnables. PremiĂšrement, un cas particulier avec services directs est analysĂ©. En considĂ©rant une cara ctĂ©ristique spĂ©cifique du problĂšme de conception de rĂ©seaux de services directs nous dĂ©veloppons un nouvel algorithme de recherche avec tabous. Un voisinage par cycles est privilĂ©giĂ© Ă  cet effet. Celui-ci est basĂ© sur la distribution du flot circulant sur les blocs selon les cycles issus du rĂ©seau rĂ©siduel. Un algorithme basĂ© sur l’ajustement de pente est dĂ©veloppĂ© pour le modĂšle complet, et nous proposons une nouvelle mĂ©thode, appelĂ©e recherche ellipsoidale, permettant d’amĂ©liorer davantage la qualitĂ© de la solution. La recherche ellipsoidale combine les bonnes solutions admissibles gĂ©nĂ©rĂ©es par l’algorithme d’ajustement de pente, et regroupe les caractĂ©ristiques des bonnes solutions afin de crĂ©er un problĂšme Ă©lite qui est rĂ©solu de facon exacte Ă  l’aide d’un logiciel commercial. L’heuristique tire donc avantage de la vitesse de convergence de l’algorithme d’ajustement de pente et de la qualitĂ© de solution de la recherche ellipsoidale. Les tests numĂ©riques illustrent l’efficacitĂ© de l’heuristique proposĂ©e. En outre, l’algorithme reprĂ©sente une alternative intĂ©ressante afin de rĂ©soudre le problĂšme simplifiĂ©. Enfin, nous Ă©tudions le modĂšle complet Ă  trĂšs grande Ă©chelle. Une heuristique hybride est dĂ©veloppĂ©e en intĂ©grant les idĂ©es de l’algorithme prĂ©cĂ©demment dĂ©crit et la gĂ©nĂ©ration de colonnes. Nous proposons une nouvelle procĂ©dure d’ajustement de pente oĂč, par rapport Ă  l’ancienne, seule l’approximation des couts liĂ©s aux services est considĂ©rĂ©e. La nouvelle approche d’ajustement de pente sĂ©pare ainsi les dĂ©cisions associĂ©es aux blocs et aux services afin de fournir une dĂ©composition naturelle du problĂšme. Les rĂ©sultats numĂ©riques obtenus montrent que l’algorithme est en mesure d’identifier des solutions de qualitĂ© dans un contexte visant la rĂ©solution d’instances rĂ©elles.This thesis studies a scheduled service network design problem for rail freight transportation planning. Rails follow a special two level consolidation organization, and the car-to-block, block-to-service handling procedure complicates daily operations. In this research, the two consolidation processes as well as the operation schedule are considered simultaneously, and by solving this problem, we provide an overall cost-effective operating plan, including blocking policy, train routing, scheduling, make-up policy and traffic distribution. In order to describe various rail operations at the tactical level, we extend the physical network and construct a 3-layer time-space structure, in which the time dimension takes into consideration the temporal impacts on operations. Furthermore, operations on trains, blocks, and cars are described in different layers. Based on this network structure, we model the rail planning problem to a service network design formulation. The proposed model relies on a complex mixed-integer programming formulation. The problem is very hard to solve due to the computational difficulty as well as the tremendous size of the application instances. Three versions of the problem are studied, which are the simplified model (with only non-stop services), complete model (with both non-stop and multi-stop services) and very-large-scale complete model. Heuristic algorithms are developed to provide good feasible solutions in reasonable computing efforts. A special case with non-stop services is first studied. According to a specific characteristic of the direct service network design problem, we develop a tabu search algorithm. The tabu search moves in a cycle-based neighborhood, where flows on blocks are re-distributed according to the cycles in a conceptual residual network. A slope scaling based algorithm is developed for the complete model, and we propose a new method, called ellipsoidal search, to further improve the solution quality. Ellipsoidal search combines the good feasible solutions generated from the slope scaling, and collects the features of good solutions into an elite problem, and solves it with exact solvers. The algorithm thus takes advantage of the convergence speed of slope scaling and solution quality of ellipsoidal search, and is proven effective. The algorithm also presents an alternative for solving the simplified problem. Finally, we work on the very-large-size complete model. A hybrid heuristic is developed by integrating the ideas of previous research with column generation. We propose a new slope scaling scheme where, compared with the previous scheme, only approximate service costs instead of both service and block costs are considered. The new slope scaling scheme thus separates the block decisions and service decisions, and provide a natural decomposition of the problem. Experiments show the algorithm is good to solve real-life size instances

    High-Speed Rail Projects in the United States: Identifying the Elements of Success-Part 2, MTI 06-03

    Get PDF
    In August 2005, the Mineta Transportation Institute issued the report, High-Speed Rail Projects in the United States: Identifying the Elements for Success. The report noted that since the 1960s, highspeed ground transportation (HSGT) has “held the promise of fast, convenient, and environmentally sound travel for distances between 40 and 600 miles.” After briefly discussing the different experiences with HSGT between the United States and its Asian and European counterparts, the report proceeded to review three U.S. cases—Florida, California, and the Pacific Northwest—as a means for identifying lessons learned for successfully implementing high-speed rail (HSR) in the United States. This report is, in essence, volume 2 of the previous study. Also using a comparative case study approach, this effort adds to the earlier work with three additional cases—the Chicago Hub, the Keystone Corridor, and the Northeast Corridor (NEC). As with the earlier report, the goal of this study is to identify lessons learned for successfully implementing HSR in the United States. Given the early stages of most of these projects, “success” is defined by whether a given HSR project is still actively pursuing development or funding. However, in the case of the Northeast Corridor, a fuller discussion of success is provided since HSR has been implemented on that corridor for some time now

    Investing in Mobility: Freight Transport in the Hudson Region

    Get PDF
    Proposes a framework for assessing alternative investments in freight rail, highway, and transit capacity that would increase the ability to improve mobility and air quality in the New York metropolitan area

    Analysis of Alaska Transportation Sectors to Assess Energy Use and Impacts of Price Shocks and Climate Change Legislation

    Get PDF
    We analyzed the use of energy by Alaska’s transportation sectors to assess the impact of sudden fuel prices changes. We conducted three types of analysis: 1) Development of broad energy use statistics for each transportation sector, including total annual energy and fuel use, carbon emissions, fuel use per ton-mile and passenger-mile, and cost of fuel per ton-mile and passenger-mile. 2) Economic input-output analysis of air, rail, truck, and water transportation sectors. 3) Adjustment of input-output modeling to reflect sudden fuel price changes to estimate the potential impact on industry output and employment. Alaska air transportation used approximately 1.9 billion gallons of fuel annually; 961 million gallons were used for intra-state and exiting Alaska flights. Water transportation used 101.8 million gallons annually, approximately 84.3 million gallons for intra-state and exiting segments. Railroad and truck transportation used 5.1 and 8.8 million gallons annually, respectively. Simulated fuel price increases resulted in an estimated 456.8millioninvalue−addedlossestotheAlaskaeconomythroughtheincreaseincostoftransportationservices,aswellasanequivalentlossinincometoAlaskahouseholdof456.8 million in value-added losses to the Alaska economy through the increase in cost of transportation services, as well as an equivalent loss in income to Alaska household of 26.8 million. A carbon emissions tax would have the greatest impact on the cost of air transportation services followed by water, trucking and rail.309002 DTRT06-G-0011List of Figures / List of Tables / Acknowledgements / Abstract / Executive Summary / Introduction / Background / Research Approach / Findings and Applications / Conclusions / References / Appendix A. Marine Transportation Companies / Appendix B. Barge Fuel Use Calculations / Appendix C. Data Dictionary of Variables and Sources Used for Aviation Fuel Estimates / Appendix D. Glossary of Economic Impact Term

    Transport in the Trans-Pennine Corridor: Present Conditions and Future Options. Interregional Study Working Paper 3.

    Get PDF
    This paper reports on a desk study carried out by the Institute for Transport Studies as part of a wider study of opportunities for inter-regional working in the trans-Pennine corridor, considering economic, environmental and transport issues. It draws together available information on transport and movement flows in the trans-Pennine corridor. These patterns of movement are examined from a broad perspective which considers intra-regional, inter- regional and international movements within and across the study area. The report proposes a regional package approach to transport, based on demand management and modal transfer

    Improving sustainability through intelligent cargo and adaptive decision making

    Get PDF
    In the current society, logistics is faced with the challenge to meet more stringent sustainability goals. Shippers and transport service providers both aim to reduce the carbon footprint of their logistic operations. To do so, optimal use of logistics resources and physical infrastructure should be aimed for. An adaptive decision making process for the selection of a specific transport modality, transport provider and timeslot (aimed at minimisation of the carbon footprint) enables shippers to achieve this. This requires shippers to have access to up-to-date capacity information from transport providers (e.g. current and scheduled loading status of the various transport means and information on carbon footprint) and traffic information (e.g. city logistics and current traffic information). A prerequisite is an adequate infrastructure for collaboration and open exchange of information between the various stakeholders in the logistics value chain to obtain the up-to-date information. This paper gives a view on how such an advanced information infrastructure can be realised, currently being developed within the EU iCargo project. The paper describes a reference logistics value chain, including business benefits for each of the roles in the logistics value chain of aiming for sustainability. A case analysis is presented that reflects a practical situation in which the various roles collaborate and exchange information for realizing sustainability goals, using adaptive decision making for selecting a transport modality, transport provider, and timeslot. A high-level overview is provided of the requirements on and technical implementation of the supporting advanced infrastructure for collaboration and open information exchange.In the current society, logistics is faced with the challenge to meet more stringent sustainability goals. Shippers and transport service providers both aim to reduce the carbon footprint of their logistic operations. To do so, optimal use of logistics resources and physical infrastructure should be aimed for. An adaptive decision making process for the selection of a specific transport modality, transport provider and timeslot (aimed at minimisation of the carbon footprint) enables shippers to achieve this. This requires shippers to have access to up-to-date capacity information from transport providers (e.g. current and scheduled loading status of the various transport means and information on carbon footprint) and traffic information (e.g. city logistics and current traffic information). A prerequisite is an adequate infrastructure for collaboration and open exchange of information between the various stakeholders in the logistics value chain to obtain the up-to-date information. This paper gives a view on how such an advanced information infrastructure can be realised, currently being developed within the EU iCargo project. The paper describes a reference logistics value chain, including business benefits for each of the roles in the logistics value chain of aiming for sustainability. A case analysis is presented that reflects a practical situation in which the various roles collaborate and exchange information for realizing sustainability goals, using adaptive decision making for selecting a transport modality, transport provider, and timeslot. A high-level overview is provided of the requirements on and technical implementation of the supporting advanced infrastructure for collaboration and open information exchange.In the current society, logistics is faced with the challenge to meet more stringent sustainability goals. Shippers and transport service providers both aim to reduce the carbon footprint of their logistic operations. To do so, optimal use of logistics resources and physical infrastructure should be aimed for. An adaptive decision making process for the selection of a specific transport modality, transport provider and timeslot (aimed at minimisation of the carbon footprint) enables shippers to achieve this. This requires shippers to have access to up-to-date capacity information from transport providers (e.g. current and scheduled loading status of the various transport means and information on carbon footprint) and traffic information (e.g. city logistics and current traffic information). A prerequisite is an adequate infrastructure for collaboration and open exchange of information between the various stakeholders in the logistics value chain to obtain the up-to-date information. This paper gives a view on how such an advanced information infrastructure can be realised, currently being developed within the EU iCargo project. The paper describes a reference logistics value chain, including business benefits for each of the roles in the logistics value chain of aiming for sustainability. A case analysis is presented that reflects a practical situation in which the various roles collaborate and exchange information for realizing sustainability goals, using adaptive decision making for selecting a transport modality, transport provider, and timeslot. A high-level overview is provided of the requirements on and technical implementation of the supporting advanced infrastructure for collaboration and open information exchange

    High-Speed Projects in the United States: Identifying the Elements for Success-Part 1, MTI Report 05-01

    Get PDF
    For almost half a century, high-speed ground transportation (HSGT) has held the promise of fast, convenient, and environmentally sound travel for distances between 40 and 600 miles. While a number of HSGT systems have been developed and deployed in Asia and Europe, none has come close to being implemented in the United States. Yet this is not for lack of trying. There have been several efforts around the country, most of which have failed, some of which are still in the early stages, and a few of which might come to pass. The goal of this study was to identify lessons learned for successfully developing and implementing high-speed rail (HSR) in the United States. Through a broad literature review, interviews, and three specific case studies—Florida, California, and the Pacific Northwest—this study articulates those lessons and presents themes for future consideration

    Integer programming based solution approaches for the train dispatching problem

    Get PDF
    Railroads face the challenge of competing with the trucking industry in a fastpaced environment. In this respect, they are working toward running freight trains on schedule and reducing travel times. The planned train schedules consist of departure and arrival times at main stations on the rail network. A detailed timetable, on the other hand, consists of the departure and arrival times of each train in each track section of its route. The train dispatching problem aims to determine detailed timetables over a rail network in order to minimize deviations from the planned schedule. We provide a new integer programming formulation for this problem based on a spacetime networkÍŸ we propose heuristic algorithms to solve it and present computational results of these algorithms. Our approach includes some realistic constraints that have not been previously considered as well as all the assumptions and practical issues considered by the earlier works
    • 

    corecore