Distance and time in intermodal goods transport networks in Europe: A generic approach

This paper is about distance and time as factors of competitiveness of intermodal transport. It reviews the relevance of the factors, evaluates time models in practice, compares network distances and times in alternative bundling networks with geometrically varied layouts, and points out how these networks perform in terms of vehicle scale, frequency and door-to-door time. The analysis focuses on intermodal transport in Europe, especially intermodal rail transport, but is in search for generic conclusions. The paper does not incorporate the distance and time results in cost models, and draws conclusions for transport innovation, wherever this is possible without cost modelling. For instance, the feature vehicle scale, an important factor of transport costs, is analysed and discussed.Distance and time are important factors of competitiveness of intermodal transport. They generate (direct) vehicle costs and – via transport quality – indirect costs to the customers. Clearly direct costs/prices are the most important performance of the intermodal transport system. The relevance of quality performances is less clarified. Customers emphasise the importance of a good match between the transport and the logistic system. In this framework (time) reliability is valued high. Often transport time, arrival and departure times, and frequency have a lower priority. But such conclusions can hardy be generalised. The range of valuations reflects the heterogeneity of situations. Some lack of clarity is obviously due to overlapping definitions of different performance types.The following parts of the paper are about two central fields of network design, which have a large impact on transport costs and quality, namely the design of vehicle roundtrips (and acceleration of transport speed) and the choice of bundling type: do vehicles provide direct services or run in what we call complex bundling networks? An example is the hub-and-spoke network. The objective of complex bundling is to increase vehicle scale and/or transport frequency even if network volumes are restricted. Complex bundling requires intermediate nodes for the exchange of load units. Examples of complex bundling networks are the hub-and-spoke network or the line network.Roundtrip and bundling design are interrelated policy fields: an acceleration of the roundtrip speed, often desirable from the cost point of view, can often only be carried out customer friendly, if the transport frequency is increased. But often the flow size is not sufficient for a higher frequency. Then a change of bundling model can be an outcome.Complex bundling networks are known to have longer average distances and times, the latter also due to the presence of additional intermediate exchange nodes. However, this disadvantage is – inside the limits of maximal vehicle sizes – overruled by the advantage of a restricted number of network links. Therefore generally, complex bundling networks have shorter total vehicle distances and times. This expression of economies of scale implies lower vehicle costs per load unit.The last part of the paper presents door-to-door times of load units of complex bundling networks and compares them with unimodal road transport. The times of complex bundling networks are larger than that of networks with direct connections, but nevertheless competitive with unimodal road transport, except for short distances.     

Stochastic freight flow patterns: implications for fleet optimization

Trucking, rail and other types of transportation networks share the common feature of moving equipment and crews between spatially separated terminals to accommodate the transportation of goods or people. This paper develops measures for temporal and spatial imbalances in freight flows, and applies these measures to a major trucking network. Fundamentally, the randomness inherent to a system of terminals is mitigated by pooling freight flows among terminal groups, and by pooling freight flows over many time periods. In the terminal network that we examined, long-run freight imbalances ensure that empty equipment movements must equal or exceed 13.3% of loaded movements at individual terminals and 8.2% of loaded movements at terminal groups. Due to short-run freight imbalances, the number of empty movements could increase by about 50% over the long-run average; greater increases would occur if equipment flows must be balanced on each travel lane. ©     

Gantry crane operations to transfer containers between trains: A simulation study of a Spanish terminal

Freight transfer operations are critical in combined transport networks. In this paper a simulation model and modelling approach to the transfer of cargo between trains at rail terminals is presented. The model is used to study the Port-Bou terminal, the main intermodal terminal at the Spanish-French frontier. Four different gantry crane operation modes to interchange containers between trains are evaluated. These operation rules are tested in several scenarios to examine the critical factors of the system and the best operation rule for each situation. Latest generation software is used to develop the model that incorporates modular programming and enhanced graphic systems for output representation. It allows a dynamic display of the simulated system and, likewise, the possibility of developing modules that can be reused in other studies. The research shows how simulation can be a useful planning tool in the rail transportation context.     

New operating concepts for intermodal transport: The mega hub in Hanover/Lehrte in Germany

In intermodal logistics, combined transport operators and railway companies are engaged in the development of efficient block train concepts. The proportion of transport using single railway wagons is decreasing because of its poor time-quality ratio. In future, transport services will be focussed on industrial zones and large cities that offer the transport volumes required for direct train operation. In this regard, it will become more difficult for regions with smaller load volumes to be integrated into a combined transport network. In order to confront this trend, new concepts for bundling transport volumes have to be developed. One such concept is the 'mega hub'. The core idea is to interchange load units between several block trains during a short stop at an intermodal terminal. The paper provides an overview of the operating concept of the mega hub and the opportunities for intermodal transport operators.     

Storage space allocation in container terminals

Container terminals are essential intermodal interfaces in the global transportation network. Efficient container handling at terminals is important in reducing transportation costs and keeping shipping schedules. In this paper, we study the storage space allocation problem in the storage yards of terminals. This problem is related to all the resources in terminal operations, including quay cranes, yard cranes, storage space, and internal trucks. We solve the problem using a rolling-horizon approach. For each planning horizon, the problem is decomposed into two levels and each level is formulated as a mathematical programming model. At the first level, the total number of containers to be placed in each storage block in each time period of the planning horizon is set to balance two types of workloads among blocks. The second level determines the number of containers associated with each vessel that constitutes the total number of containers in each block in each period, in order to minimize the total distance to transport the containers between their storage blocks and the vessel berthing locations. Numerical runs show that with short computation time the method significantly reduces the workload imbalance in the yard, avoiding possible bottlenecks in terminal operations.     

Automated guided vehicle system for two container yard layouts

The explosive growth in the freight volumes has put a lot of pressure on seaport authorities to find better ways of doing daily operations in order to improve the performance and to cope with avalanches of containers processing at container terminals. Advanced technologies, and in particular automated guided vehicle systems (AGVS), have been recently proposed as possible candidates for improving the terminal’s efficiency not only due to their abilities of significantly improving the performance but also to the repetitive nature of operations in container terminals. The deployment of AGVS may not be as effective as expected if the container terminal suffers from a poor layout. In this paper, simulation models are developed and used to demonstrate the impact of automation and terminal layout on terminal performance. In particular, two terminals with different but commonly used yard configurations are considered for automation using AGVS. A multi attribute decision making (MADM) method is used to assess the performance of the two terminals and determine the optimal number of deployed automated guided vehicles (AGVs) in each terminal. The simulation results demonstrate that substantial performance can be gained using AGVS. Furthermore, the yard layout has an effect on the number of AGVs used and on performance.     

A generic system dynamics based tool for airport terminal performance analysis

Decision making for airport terminal planning, design and operations is a challenging task, since it should consider significant trade-offs regarding alternative operational policies and physical terminal layout concepts. Existing models and tools for airport terminal analysis and performance assessment are too specific (i.e., models of specific airports) or general simulation platforms that require substantial airport modelling effort. In addition, they are either too detailed (i.e., microscopic) or too aggregate (i.e., macroscopic), affecting, respectively, the flexibility of the model to adapt to any airport and the level of accuracy of the results obtained. Therefore, there is a need for a generic decision support tool that will incorporate sufficient level of detail for assessing airport terminal performance. To bridge this gap, a mesoscopic model for airport terminal performance analysis has been developed, that strikes a balance between flexibility and realistic results, adopting a system dynamics approach. The proposed model has a modular architecture and interface, enabling quick and easy model building and providing the capability of being adaptable to the configuration and operational characteristics of a wide spectrum of airport terminals in a user-friendly manner. The capabilities of the proposed model have been demonstrated through the analysis of the Athens International Airport terminal.     

Optimal assignment for check-in counters based on passenger arrival behaviour at an airport

Establishing how to utilize check-in counters at airport passenger terminals efficiently is a major concern facing airport operators and airlines. Inadequate terminal capacity and the inefficient utilization of facilities such as check-in counters are major factors causing congestion and delays at airport passenger terminals. However, such delays and congestion can be reduced by increasing the efficiency of check-in counter operations, based on an understanding of passengers' airport access behaviour. This paper presents an assignment model for check-in counter operations, based on passengers' airport arrival patterns. In setting up the model, passenger surveys are used to determine when passengers arrive at the airport terminals relative to their flight departure times. The model then uses passenger arrival distribution patterns to calculate the most appropriate number of check-in counters and the duration of time that each counter should be operated. This assignment model has been applied at the Seoul Gimpo International Airport in Korea. The model provides not only a practical system for the efficient operations of time-to-time check-in counter assignments, but also a valuable means of developing effective longer-term solutions to the problem of passenger terminal congestion and delays. It also offers airlines a means of operating check-in counters with greater cost effectiveness, thus leading to enhanced customer service.     

Braess' paradox in a generalised traffic network

Braess' paradox illustrates situations when adding a new link to a transport network might lead to an equilibrium state in which travel times of users will increase. The classical network configuration introduced by Braess in 1968 to demonstrate the paradox is of fundamental significance because Valiant and Roughgarden showed in 2006 that ‘the “global” behaviour of an equilibrium flow in a large random network is similar to that in Braess' original four‐node example’. Braess' paradox has been studied mainly in the context of the classical problem introduced by Braess and his colleagues, assuming a certain type of symmetry in networks. Specifically, two pairs of links in those networks are assumed to have the same volume‐delay functions. The occurrence of Braess' paradox for this specific case of network symmetry was investigated by Pas and Principio in 1997. Such a symmetry is not common in real‐life networks because the parameters of volume‐delay functions are associated with roads physical and functional characteristics, which typically differ from one link to another. This research provides an extension of previous studies on Braess' paradox by considering arbitrary volume‐delay functions, that is, symmetry properties are not assumed for any of the network's links and the occurrence of Braess' paradox is studied for a general configuration. Copyright © 2014 John Wiley & Sons, Ltd.     

An Institutional Analysis of Coordination in Liberalized Port-related Railway Chains: An Application to the Port of Rotterdam

Abstract

The European railway market has gone through a period of liberalization over the last two decades. The liberalization of the railway market has also affected port-related railway transport. Efficient port-related transport chains are key in the competition among ports, however providing this efficiency is to a large extent a coordination challenge. Many forms of coordination are needed to ensure that the railway chain operates efficiently, including the bundling of cargo, and good organization between railway companies, terminal operators and the infrastructure managers to realize an efficient use of assets. From the literature, it appears that less attention has been paid to the economic organization of port-related railway transport in general, and specifically in the new liberalized institutional environment. The goal of this paper is to come up with a framework to better understand the issue of coordination in port-related railway chains in a liberalized institutional environment. This paper presents a conceptual framework rooted in Transaction Cost Economics (TCE). Based on an in-depth study into coordination in liberalized container railway market at the Port of Rotterdam, empirical illustrations are used to adjust the TCE approach toward a dynamic model influenced by Douglas North's theory on economic and institutional change. Empirics from the port of Rotterdam show that new players have entered the railway market and their role has changed. This paper shows that coordination of railway operations has become more complex after the regime change. From a port perspective, liberalization does not lead to an optimal allocation of resources in a process that is highly operationally interdependent. In the liberalized environment, coordination arrangements are necessary to enable efficient coordination of railway operations in Rotterdam.     

Short-term shift setting and manpower supplying under stochastic demands for air cargo terminals

A good air cargo terminal manpower supply plan helps terminals deal efficiently with their cargos and reduces their operating costs. To design a good air cargo terminal manpower supply plan, a terminal has to consider not only its operating costs, but also the uncertainty of the manpower demand in actual operations. However, most air cargo terminals in Taiwan currently depend on staff experience with a fixed demand when establishing the manpower supply plan, which is neither effective nor efficient. We have developed two stochastic-demand manpower supply plan models for air cargo terminals that can resolve stochastic demands occurring in practice. The objectives of both models are to minimize the total man-hour cost, subject to the related operating constraints. The models are formulated as integer/mixed integer linear programs. To evaluate the two stochastic-demand models under stochastic demands, we have also developed two deterministic-demand manpower supply plan models, by suitably modifying two stochastic-demand models, respectively, and an evaluation method. Here, we perform a case study using real operating data from a Taiwan air cargo terminal. The preliminary results are good, showing that the models could be useful for planning air cargo terminal manpower supply.

Modeling the cost sensitivity of intermodal inland waterway terminals: A scenario based approach

Cost characteristics of differently sized inland waterway terminals (IWTs) have not received much scientific attention. This observation is remarkable given the importance of costs in transportation decision-making. Classification of differently sized IWTs and their cost structure will lead to more insight into the container cost per terminal. Therefore, the goal of our research was to determine both the characteristics of the cost structure associated with different inland waterway (IWW) container terminal types and the sensitivity of the system to cost/TEU changes in input and operational conditions. We show that terminals with a higher container throughput encounter fewer costs, and can therefore charge a lower price. Assumed delays of 2 h per day on the waterside cause a 4.7–6.6% cost increase per container, mainly caused by extra labor costs. It is also assumed that the changing climate will influence terminal operations and results in extreme water levels (lasting two weeks occurring four times a year) causing a cost increase of 1.0–3.4%. Subsidies can cause cost reductions of 0.3–10.4% depending on the exact form, with the smaller terminals benefiting more because their investment costs are higher relative to operational costs. A subsidy can lower costs by up to 10.4%, but it is questionable whether small and medium terminals will have a lower cost price than the market price, showing that it is important for small and medium terminals to quickly grow in size.     

A literature review of flexible development of airport terminals

The Master Plan has long been the traditional go-to approach to airport development. It was originally conceived for a scenario of stable growth. In recent decades, however, the airport industry has undergone substantial structural changes, with the traditional Master Plan progressively revealing limitations with regard to airports coping with the market’s unpredictability. There have since been increased calls for flexibility in the approach as an alternative or as a complement to the traditional Master Plan. A flexible development plan helps to accommodate changes within terminals. This paper presents a review of the current literature on airport terminal flexibility, covering a total of 19 reference works. The works were analysed in terms of the concepts, definitions and deployment frameworks, or similar. The review reveals that research in airport terminal flexibility is still in its early stages. A consensual definition has yet to be defined and no robust framework for deploying flexibility has been defined. We propose a new definition of flexible development. Furthermore, flexibility has been studied essentially in the context of expansion. However, in certain regions where land availability is scarce, other forms of airport development may be more important. We conclude the paper with suggestions for future research areas.     

Freighter operators' choice of airport: a three‐stage process

With increasing levels of congestion at the major cargo hubs and further restrictions on noise and night‐time flying, freighter operators' airport choice is a complex and important issue. The aim is to identify the factors that affect the airport choice of freighter operators through a review of the published literature. The literature reviewed includes work relating to passenger hub location, airport quality and airline network configuration, and other works relating to airport choice to paint a full picture of the current research in this area. The literature shows that freighter operators initially choose a shortlist of possible airports based on geography and then investigate any restrictions in place, such as capacity caps or noise limits that might block operations from that airport. Only when these hurdles have been cleared do freighter operators consider attributes of airport quality such as charges and terminal facilities, as well as other influences such as freight forwarder presence and airport marketing. Of particular prominence is the impact of legislation on airport choice.     

An analysis of the Spanish high capacity road network criticality

The analysis of complex networks has been carried out in different fields using an ample variety of method and concepts. Recently, in the general literature of regional economics, the concepts of resilience, connectivity, vulnerability and criticality have been gaining their momentum. The aim of this paper is to provide an analytical framework, using well-known accessibility indicators, in order to calculate the critical links or road sections of the Spanish high-capacity road network. Our analysis will be based on approximately four hundred sections that will be classified in five different groups according to their criticality degree in the whole network. Our analysis will be complemented with the comparison of the results obtained in five different scenarios, namely the average criticality using the effects on the whole country, Madrid, Barcelona, Valencia and Pontevedra. Furthermore, the paper will also analyze what kind of intrinsic characteristics of the sections favor or not the links’ criticality using a method based on a classification and regression tree. This analysis is crucial to understand other important concepts that are recently being studied in network and spatial economics, like, for example, resilience and vulnerability. It is concluded that the number of relations or routes, being a trunk or not, the road density and the time to Madrid capital play an important role in the criticality of the roads section in the high capacity road network.     

Predicting disruptions and their passenger delay impacts for public transport stops

Disruptions in public transport can have major implications for passengers and service providers. Our study objective is to develop a generic approach to predict how often different disruption types occur at different stations of a public transport network, and to predict the impact related to these disruptions as measured in terms of passenger delays. We propose a supervised learning approach to perform these predictions, as this allows for predictions for individual stations for each time period, without the requirement of having sufficient empirical disruption observations available for each location and time period. This approach also enables a fast prediction of disruption impacts for a large number of disruption instances, hence addressing the computational challenges that rise when typical public transport assignment or simulation models would be used for real-world public transport networks. To improve transferability of our study results, we cluster stations based on their contribution to network vulnerability using unsupervised learning. This supports public transport agencies to apply the appropriate type of measure aimed to reduce disruptions or to mitigate disruption impacts for each station type. Applied to the Washington metro network, we predict a yearly passenger delay of 5.9 million hours for the total metro network. Based on the clustering, five different types of station are distinguished. Stations with high train frequencies and high passenger volumes located at central trunk sections of the network show to be most critical, along with start/terminal and transfer stations. Intermediate stations located at branches of a line are least critical.

     

In Search of the Link between Ship Size and Operations

Abstract

Since 1990s the liner shipping industry has faced a period of restructuring and consolidation, and been confronted with a continuing increase in container vessel scale. The impact of these changes is noticeable in trade patterns, cargo handling methods and shipping routes, in short ‘operations’. After listing factors influencing size, growth in container ship size is explained by economies of scale in deploying larger vessels. In order to quantify economies of scale, this paper uses the liner service cash flow model. A novelty in the model is the inclusion of +6000-20-foot Equivalent Unit (TEU) vessels and the distinction in costs between single and twin propeller units on ships. The results illustrate that scale economies have been – and will continue to be – the driving force behind the deployment of larger container vessels. The paper then assesses the link between ship size and operations, given current discussions about the increase in container vessel scale. It is found that (a) ship size and operations are linked; (b) optimal ship size depends on transport segment (deep-sea vs. short-sea shipping, SSS), terminal type (transhipment terminals vs. other terminals), trade lane (East-West vs. North-South trades) and technology; and (c) a ship optimal for one trade can be suboptimal for another.     

The design of a terminal for dangerous goods

This paper aims at examining the possibility of setting up a model terminal for the transportation of dangerous goods. It should be designed in such a manner that its use would be possible for any kind of transportation.

This consideration has been prompted by the interface between transportation planning and technology, as well as by the tendency for harmonizing international recommendations pertaining to the transportation and handling of dangerous goods, especially during the last decades where unified transport has gained ground due to the advantages provided for the safe consignment of dangerous cargoes.

Since the large increase in terminal productivity is due to the heavy investments that were effected in terminal installations and to the modernization of the administration‐management of terminals, a mathematical simulation has been adopted to assist the determination of the capacity of a terminal for dangerous goods.

It is evident that different criteria and various assumptions have been taken into account in order to facilitate a deeper analysis, without ignoring the contribution of dangerous goods to the socio‐economic development.

From the outset of the study, it was already clear that the said process will make it possible to present—as a model—a simple but well defined situation for the purpose of drawing useful conclusions.     

Hub location with flow economies of scale

A characteristic feature of hub and spoke networks is the bundling of flows on the interhub links. This agglomeration of flows leads to reduced travel costs across the interhub links. Current models of hub location do not adequately model the scale economies of flow that accrue due to the agglomeration of flows. This paper shows that current hub location models, by assuming flow-independent costs, not only miscalculate total network cost, but may also erroneously select optimal hub locations and allocations. The model presented in this paper more explicitly models the scale economies that are generated on the interhub links and in doing so provides a more reliable model representation of the reality of hub and spoke networks.