Accurate estimation of the coefficient of friction (CoF) is essential to accurately modeling railroad dynamics, reducing maintenance costs, and increasing safety factors in rail operations. The assumption of a constant CoF is popularly used in simulation studies for ease of implementation, however many evidences demonstrated that CoF depends on various dynamic parameters and instantaneous conditions. In the real world, accurately estimating the CoF is difficult due to effects of various uncertain parameters, such as wheel and rail materials, rail roughness, contact patch, and so on. In this study, the newly developed 3-D nonlinear CoF model for the dry rail condition is introduced and the CoF variation is tested using this model with dynamic parameters estimated from the wheel-rail simulation model. In order to account for uncertain parameters, a stochastic analysis using the polynomial chaos (poly-chaos) theory is performed using the CoF and wheel-rail dynamics models. The wheel-rail system at a right traction wheel is modeled as a mass-spring-damper system to simulate the basic wheel-rail dynamics and the CoF variation. The wheel-rail model accounts for wheel-rail contact, creepage effect, and creep force, among others. Simulations are performed at train speed of 20 m/s for 4 sec using rail roughness as a unique excitation source. The dynamic simulation has been performed for the deterministic model and for the stochastic model. The dynamics results of the deterministic model provide the starting point for the uncertainty analysis. Six uncertain parameters have been studied with an assumption of 50% uncertainty, intentionally imposed for testing extreme conditions. These parameters are: the maximum amplitude of rail roughness (MARR), the wheel lateral displacement, the track stiffness and damping coefficient, the sleeper distance, and semi-elliptical contact lengths. A symmetric beta distribution is assumed for these six uncertain parameters. The PDF of the CoF has been obtained for each uncertain parameter study, for combinations of two different uncertain parameters, and also for combinations of three different uncertain parameters. The results from the deterministic model show acceptable vibration results for the body, the wheel, and the rail. The introduced CoF model demonstrates the nonlinear variation of the total CoF, the stick component, and the slip component. In addition, it captures the maximum CoF value (initial peak) successfully. The stochastic analysis results show that the total CoF PDF before 1 sec is dominantly affected by the stick phenomenon, while the slip dominantly influences the total CoF PDF after 1 sec. Although a symmetric distribution has been used for the uncertain parameters considered, the uncertainty in the response obtained displayed a skewed distribution for some of the situations investigated. The CoF PDFs obtained from simulations with combinations of two and three uncertain parameters have wider PDF ranges than those obtained for only one uncertain parameter. FFT analysis using the rail displacement has been performed for the qualitative validation of the stochastic simulation result due to the absence of the experimental data. The FFT analysis of the deterministic rail displacement and of the stochastic rail displacement with uncertainties demonstrates consistent trends commensurate with loss of tractive efficiency, such as the bandwidth broadening, peak frequency shifts, and side band occurrence. Thus, the FFT analysis validates qualitatively that the stochastic modeling with various uncertainties is well executed and is reflecting observable, real-world results. In conclusions, the development of an effective model which helps to understand the nonlinear nature of wheel-rail friction is critical to the progress of railroad component technology and rail safety. In the real world, accurate estimation of the CoF at the wheel-rail interface is very difficult since it is influenced by several uncertain parameters as illustrated in this study. Using the deterministic CoF value can cause underestimation or overestimation of CoF values leading to inaccurate decisions in the design of the wheel-rail system. Thus, the possible PDF ranges of the CoF according to key uncertain parameters must be considered in the design of the wheel-rail system. / Ph. D.

Early detection of rail defects is necessary for preventing derailments and costly damage to the train and railway infrastructure. A rail surface flaw can quickly propagate from a small fracture to a broken rail after only a few train cars have passed over it. Rail defect detection is typically performed by using an instrumented car or a separate railway monitoring vehicle. Rail surface irregularities can be measured using accelerometers mounted to the bogie side frames or wheel axles. Typical signal processing algorithms for detecting defects within a vertical acceleration signal use a simple thresholding routine that considers only the amplitude of the signal. As a result, rail surface defects that produce low amplitude acceleration signatures may not be detected, and special track components that produce high amplitude acceleration signatures may be flagged as defects. The focus of this research is to develop an intelligent signal processing algorithm capable of detecting and classifying various rail surface irregularities, including defects and special track components. Three algorithms are proposed and validated using data collected from an instrumented freight car. For the first two algorithms, one uses a windowed Fourier Transform while the other uses the Wavelet Transform for feature extraction. Both of these algorithms use an artificial neural network for feature classification. The third algorithm uses the Wavelet Transform to perform a regularity analysis on the signal. The algorithms are validated with the collected data and shown to out-perform the threshold-based algorithm for the same data set. Proper training of the defect detection algorithm requires a large data set consisting of operating conditions and physical parameters. To generate this training data, a dynamic wheel-rail interaction model was developed that relates defect geometry to the side frame vertical acceleration signature. The model was generated by using combined systems dynamic modeling, and the system was solved with a developed combined lumped and distributed parameter system numerical approximation. The broken rail model was validated with real data collected from an instrumented freight car. The model was then used to train and validate the defect detection methodologies for various train and rail physical parameters and operating conditions. / Ph. D.

Le squat est un défaut de fatigue de contact apparaissant à la surface du rail et dont le mécanisme d’amorçage est mal compris. Afin de pallier ce manque, une analyse tribologique locale de la bande de roulement du rail est mise en oeuvre à proximité d’un squat naissant. Cette caractérisation révèle une anisotropie importante des couches superficielles du rail associée aux développements de Transformations Tribologiques Superficielles. Ces résultats témoignent de conditions de contact roue/rail particulières dans la zone d’étude, notamment d’un niveau d’efforts de cisaillement inhabituel pour une voie en alignement. Dans le but de valider ces observations, plusieurs essais sont effectués. D’une part les conditions de contact roue/rail dans une zone de squats sont mesurées à partir d’un train instrumenté. D’autre part, la réponse tribologique de l’acier à rail à ces conditions de contact est étudiée à travers le suivi régulier d’une zone d’essais soumise à la circulation ferroviaire. Ces essais permettent d’identifier un déséquilibre important des efforts de traction sur les bogies moteurs et des glissements locaux élevés de la roue sur le rail. Différents mécanismes d’amorçage thermo-mécaniques sont alors proposés au sein d’un schéma global de la réponse tribologique de l’acier à rail. / Squats have recently become recognised as one of the major rolling contact fatigue defects in modern railway networks for which there is currently no solution other than preventive grinding operations or costly rail renewal. To better understand the entire damage mechanism of squat, A tribological and metallurgical analysis of the rolling band and the near surface layer was performed close to an incipient squat. This characterization show a significant anisotropy of the rail surface layer associated with developments of Tribological Transformation of Surface. These results reflect some specific wheel/rail contact conditions in this squat area, including an unusual level of shear forces in a straight track. In order to validate this observations, two tests were performed. On the one hand, the contact conditions in a squat area were measured from an instrumented train. On the other hand, the tribological response of the rail steel was studied through regular monitoring of a test site subjected to railway traffic. These tests allow to identify a high imbalance of the traction forces and the presence of local slips at the wheel/rail interface. Several thermomechanical initiation mechanism of squats are then given in a overall diagram of the tribological response of rail steels.

The adhesion in the wheel-rail contact can be effectively controlled by using the friction modifier. Adhesion control can reduce excessive wear of the contact bodies or noise. The essence of this diploma thesis is to determine the optimal amount of friction modifier in wheel-rail contact depending on the climatic and operating conditions. For experimental study of the behavior of the friction modifier, the twin-disc device is used. Twin-disc simulates and controls the most important operating parameters such as speed, slip, attack angle or contact pressure. On the basis of these findings, the off-board top-of-rail lubricator system was designed. This system controls the amount of friction modifier according to current climatic and operating conditions.

The aim of this work is make a new design and technology of the low-pressure output part of rail which is made in BOSCH DIESEL s.r.o. company. In the thesis is analyzed in detail the bending test, which is part of the quality control of the low-pressure welding joint. In the next part of the thesis is proposed the process of machining of this component, followed by experimental finding of welding parameters for resistance welding. Then several pieces are welded, which are measured and tested. The results of this tests are compared with customer requirements. Finally, a technical and economic evaluation of the change is made, which will save a considerable amount of money for the company.

This diploma thesis with a view to „common rail system for 4-cylinder CI-engine“ deals with the application of modern injection system „common rail“ to already existing compression-ignition tractor engine. The diploma thesis treats of the most necessary adjustments related with the replacement of injection systems which was solved in the way of the minimum adjustments. This kind of solution deals with an economic aspect of the problem. The reconstruction contains the engineering design of development of high pressure components and the suitability of their placing on engine.The primary adjustment of the application of system „common rail“ for existing tractor engine confirmed the possibility of this reconstruction.

Cette recherche a pour objet le transport ferroviaire interurbain de passagers aux Etats-Unis dans une double acception : les services ferroviaires classiques d’Amtrak et les projets de grande vitesse ferroviaire. Il s’agit de comprendre comment les politiques publiques concernant le mode ferroviaire fonctionnent, ce qu’elles contiennent et la manière dont elles sont élaborées et portées par les différents acteurs. L’originalité de la recherche repose sur son approche multiscalaire avec un aller-retour continu entre les différentes échelles d’analyse et sur son ambition d’analyser la territorialisation des politiques en faveur du mode ferroviaire interurbain grâce à plusieurs études de cas. L’analyse met en évidence le fait que s’impose une approche bottom-up pour le portage des projets, c’est le cas notamment pour le projet californien de GVF californien et la modernisation du corridor des Cascades. Cette logique est même poussée à l’extrême avec la multiplication de ces projets ferroviaires privés qui revendiquent leur indépendance par rapport à la puissance publique tant en termes de prise de décision que de gouvernance ou de financement. Cela semble éloigner définitivement toute tentative de définition d’un schéma national pour la grande vitesse ferroviaire, sur le modèle de ce qui s’est passé dans les pays historiques de la GVF, au-delà des considérations partisanes – c’est-à-dire de l’engagement traditionnellement plus fort du parti démocrate dans les grands investissements fédéraux. Deux conclusions en ressortent : en premier lieu, une uniformisation de cet argumentaire et des préconisations pour encourager de nouvelles politiques ferroviaires – effets structurants, rôle économique de la grande vitesse, lutte contre la congestion, report modal ; en second lieu, un engagement à toutes les échelles, tangible mais à divers degrés, des acteurs publics en faveur du mode ferroviaire. Il n’y a pas de projets, portés par des acteurs publics, de nouvelles lignes exclusivement réservées à la GVF. L’essentiel des corridors à grande vitesse concerne des corridors à vitesse élevée (higher speed rail) dont certains ont vocation à devenir à plus ou moins long terme à grande vitesse comme le corridor Nord-Est. Le projet californien, quant à lui, repose en partie sur la réalisation d’une nouvelle infrastructure mais aussi sur l’utilisation de tronçons existants améliorés. La territorialisation des projets ferroviaires passe par la conception et la mise en œuvre de réseaux de transport davantage intégrés – au moins sur le plan de la desserte et de la connexion physique – selon une véritable logique réticulaire. Après analyse des projets de modernisation de corridors à vitesse élevée et de construction de nouvelles infrastructures, nous constatons l’importance des gares et une mise à l’agenda d’une meilleure coordination entre transports et urbanisme par le soutien aux quartiers de gare. En effet, un projet de corridor ferroviaire, qui se trouve au croisement d’intérêts politiques, économiques, techniques et territoriaux, est bien au centre d’un processus de territorialisation qui inscrit matériellement l’infrastructure dans les espaces urbains, et d’un processus de politisation par une mobilisation des acteurs locaux. Les projets ferroviaires apparaissent comme un instrument permettant l’implantation d’équipements à l’échelle métropolitaine (gares, pôles intermodaux) et la structuration ou la reconfiguration du tissu urbain (quartiers de gare, projets plus vastes de renouvellement d’un quartier) / The subject of this research is intercity passenger rail transportation in the United States, approached from two perspectives: Amtrak’s traditional rail services and high-speed rail projects. The aim is to understand the workings of public rail transportation policies, what they contain, and how they are developed and pursued by the different actors. The originality of the research lies in its multiscale approach, with a constant back-and-forth between the different scales of analysis, and in its use of several case studies to analyze the territorialization of intercity rail transportation policies. The analysis demonstrates the emergence of a bottom-up approach to projects, notably apparent in the Californian HSR project and in the modernization of the Cascades corridor. This process has even gone to the extreme with the proliferation of private rail projects that stress their independence from government, be it in decision-making, governance, or funding. This seems definitively to preclude any attempt to establish a national framework for high-speed rail, like those found elsewhere in the world, regardless of party-political considerations, i.e. the traditionally greater enthusiasm of the Democratic Party for large-scale federal investment. Two conclusions emerge: first, the development of uniform arguments and recommendations to encourage new rail policies, emphasizing the structuring effects and economic role of high-speed rail, congestion reduction, modal shift; second, a tangible though uneven pro-rail position among public actors at all levels. Priority is placed on improving and modernizing existing corridors for the launch of higher-speed services, and then on hybrid networks that combine different types of infrastructures. There are no publicly backed projects for new lines exclusively dedicated to high-speed rail. Most of the high-speed corridors are in fact “higher-speed” corridors, some of which are intended to become high-speed at some time in the future, such as the Northeast corridor. The territorialization of rail projects entails the design and construction of transportation networks that are more integrated – at least in terms of service provision and physical connection – and genuinely interconnected. After analyzing projects for the upgrading of higher-speed corridors and the construction of new infrastructures, we note the importance of stations and the emphasis on the need for better coordination between transportation and urbanism through support for station districts. Indeed, a rail corridor project – situated at the intersection of political, economic, technical, and territorial interests – is the nucleus of a process of territorialization that materially embeds the infrastructure within urban spaces, and of a process of politicization through the involvement of local actors. Rail projects seem to be an instrument that leads to the implantation of metropolitan scale facilities (stations, intermodal hubs) and to the shaping or reshaping of the urban fabric (station districts, larger-scale district regeneration projects)

Detta examensarbete har utförts med begäran från Trafikförvaltningen. Arbetets huvudmål är att undersöka om det är möjligt att använda värmestrålning direkt mot ytan av strömskenan för att hindra isbildning på en kortare tid då absorptiviteten är som bäst. / This dissertation has been written with the request from Trafikvörvaltningen. The study's main goal is to investigate whether it is possible to use heat radiation against the surface of the third rail to prevent ice creation during the best efficient of absorptivity.

No description available.

This thesis addresses integrated challenges within the global supply chain and intercontinental rail freight transport, establishing the foundation for a new research area. First, this thesis focuses on the development of unified SCOR-Rail Key Performance Indicators (KPIs) for intercontinental rail freight transport, as well as initial analysis on Eurasian rail freight. It also proposes various rail supply chain strategies to differentiate rail services, including efficient, continuous replenishment, and responsive rail supply chain strategies that support market segmentation and service differentiation. The proposed Integrated Tactical Planning Method (ITPM) is a supply chain-oriented planning approach for intercontinental rail freight transport. It considers the intercontinental rail freight network's complexities, such as multiple border crossings and transshipments at border crossing terminals, the unique characteristics of different train lengths across different rail systems, as well as multiple stakeholders such as terminals, railway undertakings, infrastructure providers, and shippers and forwarders. ITPM offers optimization models (I-FSND and I-SSND) that simultaneously account for both the supply chain and rail system sides. Both models simulate the complexities of intercontinental rail freight operations. The I-FSND model calculates the train service frequency on each route during the planning period, whereas the I-SSND model considers the synchronization of each order at border-crossing terminals across different rail systems. Furthermore, both models include a rejection mechanism and consider transit time differences on the same arc for the main transit, with the I-SSND model determining the duration time of each order at terminals. In the I-FSND model, a weighted goal programming method optimizes resource allocation, balancing service quality, profit, total number of accepted containers through the network, and border crossing terminals' capacity deficiency. The potential capacity deficiencies—information is useful when making future investment decisions. The ITPM is a powerful tool for intercontinental rail freight planners, the proposed optimization models I-FSND and I-SSND ensure more efficient utilization of resources while simultaneously satisfying heterogeneous transport service requirements of the supply chain. Rail planners can employ the I-FSND model for network capacity analysis across various scenarios, especially when the specific timetable of train services is not a primary concern, while I-SSND model could be used to more operational analysis. Furthermore, ITPM is not only applicable to intercontinental rail freight, but also to rail freight transport networks with multiple border crossings, such as the Trans-European Transport Network (TEN). The initial application of these models in Eurasian rail freight shows promising potential for broader implementation in intercontinental rail freight transport, particularly in creating new business opportunities to meet the diverse transport demands of the supply chain.:1 Intercontinental rail freight transport 1 1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1.1 Development of intercontinental rail freight transport . . . . . . . . . . . 1 1.1.2 Need for a supply chain-oriented planning method for intercontinental rail freight transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 Intercontinental rail freight planning problems . . . . . . . . . . . . . . . . . . . 5 1.2.1 Limitations of current rail planning . . . . . . . . . . . . . . . . . . . . . . 5 1.2.2 Intercontinental rail freight transport in supply chain planning . . . . . . 9 1.2.3 Scientific gaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 1.3 Main contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.4 Thesis outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 1.5 Collaborations in the thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2 Service quality assessment of intercontinental rail transport 20 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.2 Existing research in international freight rail transport . . . . . . . . . . . . . . . 23 2.2.1 Stakeholders and processes of international rail transport . . . . . . . . 23 2.2.2 International rail services . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 2.2.3 Current performance measurement of rail transport . . . . . . . . . . . 26 2.2.4 Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.3 Development of SCOR-Rail KPIs for international rail services . . . . . . . . . . . 28 2.3.1 Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 2.3.2 Responsiveness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 2.3.3 Flexibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 2.3.4 Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2.3.5 Asset efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 2.4 Initial assessment of Eurasian rail transport . . . . . . . . . . . . . . . . . . . . . 37 2.4.1 Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 2.4.2 Responsiveness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 2.4.3 Flexibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 2.4.4 Asset efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 2.4.5 Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 2.5 Improvement measures of current Eurasian rail transport . . . . . . . . . . . . . 43 2.5.1 Service differentiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 2.5.2 Priority rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 2.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 3 Heterogeneous rail supply chain strategies 48 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 3.2 Existing research on rail service differentiation . . . . . . . . . . . . . . . . . . . 51 3.3 Development of railway supply chain strategies . . . . . . . . . . . . . . . . . . . 53 3.3.1 Efficient RSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 3.3.2 Continuous replenishment RSC . . . . . . . . . . . . . . . . . . . . . . . . 55 3.3.3 Responsive RSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 3.4 International rail service differentiation . . . . . . . . . . . . . . . . . . . . . . . . 57 3.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 3.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 4 Integrated tactical planning method 62 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 4.2 Existing research on information integration in rail transport . . . . . . . . . . . 65 4.3 Information integration in international rail freight transport . . . . . . . . . . . 67 4.3.1 Information quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 4.3.2 Information integration phases . . . . . . . . . . . . . . . . . . . . . . . . 67 4.3.3 Information evolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 4.4 Hierarchical information integration in rail planning . . . . . . . . . . . . . . . . 70 4.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 4.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 5 Integrated planning of intercontinental rail freight transport with I-FSND model 77 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 5.2 Literature review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 5.2.1 Basics of rail planning and SND . . . . . . . . . . . . . . . . . . . . . . . . 81 5.2.2 SND in freight transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 5.2.3 Research gaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 5.2.4 Our contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 5.3 Problem Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 5.4 Mathematical Modelling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 5.4.1 Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 5.4.2 I-FSND model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 5.4.3 Weighted goal programming method . . . . . . . . . . . . . . . . . . . . . 92 5.5 Case study: Eurasian rail freight transport . . . . . . . . . . . . . . . . . . . . . . 94 5.5.1 Experimental setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 5.5.2 Scenarios generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 5.6 Results and discussions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 5.6.1 Single goal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 5.6.2 Multiple goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 5.6.3 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 5.7 Conclusion and future directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108 6 Scheduled service network design for intercontinental rail freight transport 109 6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 6.2 Literature Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 6.2.1 Intercontinental freight transport-Eurasian rail freight transport . . . . . 113 6.2.2 SSND in freight transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 6.2.3 Research gaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 6.3 Mathematical modelling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 6.3.1 Problem description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 6.3.2 Generation of the time-space network . . . . . . . . . . . . . . . . . . . . 119 6.3.3 Mathematical formulation . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 6.4 Computational Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 6.4.1 Construction of test instances . . . . . . . . . . . . . . . . . . . . . . . . . 124 6.4.2 Synchronization of orders at border crossing terminals . . . . . . . . . . 127 6.4.3 Effects of differentiating train services during main transit . . . . . . . . 129 6.4.4 Effects of delay tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 6.4.5 Impact of border crossing time of European borders . . . . . . . . . . . 134 6.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 6.6 Conclusion and future directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 7 Conclusion and future directions 140 7.1 Main conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 7.2 Recommendations for practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 7.3 Further Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146 Bibliography 148 Summary 168