The present thesis examines the performance of complex freight handling nodes with a focus on the transshipment from and to rail. Complex freight nodes can be found for example in major seaports or industrial railways of large industrial plants. When investigating the railway-specific processes of freight hubs, it has been particularly noticed that they practice an improvised rather than a scheduled operations policy, also known as timetable-free scheduling. That means that the necessary cargo handling process steps are performed rather spontaneous and without much planning efforts. The inadequate organisation of railway operations also leads to significant inefficiencies in the cargo handling capacity. This thesis is motivated by the aspiration of increasing the productivity and thus the throughput capacity of goods, wagons and trains through complex freight nodes as an overall system. The existing shortcomings shall be resolved by means of a robust hub scheduling approach which synchronises the work processes in freight yards with the preceding and succeeding links in the transport chain. By replacing the timetable-free operations in the railway yard with a process-oriented coordination mechanism based on a time windows (slot management) strategy, the railway-specific requirements shall be integrated with customer's and logistics demands. Initially, the rail-specific production processes of freight nodes are elaborated in a process analysis. It examines the properties of various terminal types, the cargo handling techniques, and the process sequences that freight trains, which pass through the hubs, are involved in. In the process analysis it is pointed out that due to the large number of actors involved in complex hubs and due to the lack of a superior coordinator, it is expected that there is a significant potential for increasing the efficiency of such nodes due to new dispatching strategies. A two-step simulation and optimisation model approach is developed to investigate the productivity of the cargo transshipment to and from rail. In the first stage of the modelling approach, the performance of freight nodes is analysed in a combined queueing and simulation environment. The model allows to examine the efficiency of individual system components and to identify bottlenecks. It is shown how the interrelationships between the various processes can have a negative influence on the terminal performance when process coordination is insufficient. In particular, it is illustrated, how the turnover rate of the hub decreases when overloaded. A central aspect of the simulation is the computation of distribution functions from observation data for determining stochastic process durations in the different areas of freight hubs. They are of essential significance for the development of the slot management system in the further course of this thesis. In the second step, the optimisation phase, slot plan sequences for the processing of trains through the freight node are developed by means of a linear programming approach. These slot plans control the allocation of railway infrastructure in the formation tracks of the marshalling yard as well as of the loading tracks in the transshipment terminals. By gradually populating stochastic data from real-life observations, the slot system is tested for robustness under realistic conditions. A stability analysis examines in several scenarios, how slot plans get influenced by various optimisation rules and external factors. In particular, unpunctual incoming freight trains have been identified as having a significant impact on the slot stability. With the development of appropriate rescheduling mechanisms it is further shown that the stability of the slot plans can be ensured even with heavy arrival time deviations. With the rescheduling approach, the slot management has been extended to a powerful tool that keeps the hub production system in a steady state, providing the necessary transparency to other involved stakeholders, particularly to railway undertakings. It even allows reducing the dwell times of trains with arrival delays and thus reduces the likelihood that these delays affect the train's subsequent trips. With the current production system, transshipment nodes were identified as the weakest link in the transport chain. The thesis shows that their position can be significantly strengthened through such a slot management in combination with a powerful rescheduling approach. The presented slot-based hub production approach optimises not only the processes of the hub itself, but also the processes for the benefit of other stakeholders in the transport chain, such as forwarders, shippers or railway undertakings.


    Zugriff

    Download


    Exportieren, teilen und zitieren



    Titel :

    Scheduling rail freight node operations through a slot allocation approach


    Weitere Titelangaben:

    Fahrplanung in Schienengüterverkehrsknoten mit Hilfe eines Slot-Management-Ansatzes


    Beteiligte:

    Erscheinungsdatum :

    2016



    Medientyp :

    Sonstige


    Format :

    Elektronische Ressource


    Sprache :

    Englisch



    Klassifikation :

    DDC:    625




    Scheduling Freight Trains in Rail-Rail Transshipment Yards

    Boysen, N. / Jaehn, F. / Pesch, E. | British Library Online Contents | 2011



    Rail freight operations in a commercial environment

    Reistrup, P. H. / International Railway Congress Association / SPOORNET | British Library Conference Proceedings | 1996


    Rail freight operations in a commercial environment

    Reistrup, P. H. | British Library Online Contents | 1996