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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Evaluation de performance d’une ligne ferroviaire suburbaine partiellement équipée d’un automatisme CBTC / Performance of a suburban railway line partially equipped with a CBTC system

Pochet, Juliette 12 January 2018 (has links)
En zone dense, la croissance actuelle du trafic sur les lignes ferroviaires suburbaines conduit les exploitants à déployer des systèmes de contrôle-commande avancés des trains, tels que les systèmes dits « CBTC » (Communication Based Train Control) jusque-là réservés aux systèmes de métro. Les systèmes CBTC mettent en œuvre un pilotage automatique des trains et permettent une amélioration significative des performances. Par ailleurs, ils peuvent inclure un module de supervision de la ligne en charge de réguler la marche des trains en cas d’aléa, améliorant ainsi la robustesse du trafic. Face au problème de régulation, la recherche opérationnelle a produit un certain nombre de méthodes permettant de répondre efficacement aux perturbations, d’une part dans le secteur métro et d’autre part dans le secteur ferroviaire lourd. En tirant profit de l’état de l’art et des avancées faites dans les deux secteurs, les travaux présentés dans ce manuscrit cherchent à contribuer à l’adaptation des fonctions de régulation des systèmes CBTC pour l’exploitation de lignes ferroviaires suburbaines. L’approche du problème débute par la construction de l’architecture fonctionnelle d’un module de supervision pour un système CBTC standard. Nous proposons ensuite une méthode de régulation basée sur une stratégie de commande prédictive et sur une optimisation multi-objectif des consignes des trains automatiques. Afin d’être en mesure d’évaluer précisément les performances d’une ligne ferroviaire suburbaine équipée d’un automatisme CBTC, il est nécessaire de s’équiper d’un outil de simulation microscopique adapté. Nous présentons dans ce manuscrit l’outil SNCF nommé SIMONE qui permet une simulation réaliste du point de vue fonctionnel et dynamique d’un système ferroviaire incluant un système CBTC. Les objectifs des travaux de thèse nous ont naturellement conduits à prendre part, avec l’équipe SNCF, à la spécification, à la conception et à l’implémentation de cet outil. Finalement, grâce à l’outil SIMONE, nous avons pu tester la méthode de régulation proposée sur des scénarios impliquant des perturbations. Afin d’évaluer la qualité des solutions, la méthode multi-objectif proposée a été comparée à une méthode de régulation individuelle basée sur une heuristique simple. La méthode de régulation multi-objectif propose de bonnes solutions au problème, dans la majorité des cas plus satisfaisantes que celles proposées par la régulation individuelle, et avec un temps de calcul jugé acceptable. Le manuscrit se termine par des perspectives de recherche intéressantes. / In high-density area, the demand for railway transportation is continuously increasing. Operating companies turn to new intelligent signaling and control systems, such as Communication Based Train Control (CBTC) systems previously deployed on underground systems only. CBTC systems operate trains in automatic pilot and lead to increase the line capacity without expensive modification of infrastructures. They can also include a supervision module in charge of adapting train behavior according to operating objectives and to disturbances, increasing line robustness. In the literature of real-time traffic management, various methods have been proposed to supervise and reschedule trains, on the one hand for underground systems, on the other hand for railway systems. Making the most of the state-of-the-art in both fields, the presented work intend to contribute to the design of supervision and rescheduling functions of CBTC systems operating suburban railway systems. Our approach starts by designing a supervision module for a standard CBTC system. Then, we propose a rescheduling method based on a model predictive control approach and a multi-objective optimization of automatic train commands. In order to evaluate the performances of a railway system, it is necessary to use a microscopic simulation tool including a CBTC model. In this thesis, we present the tool developed by SNCF and named SIMONE. It allows realistic simulation of a railway system and a CBTC system, in terms of functional architecture and dynamics. The presented work has been directly involved in the design and implementation of the tool. Eventually, the proposed rescheduling method was tested with the tool SIMONE on disturbed scenarios. The proposed method was compared to a simple heuristic strategy intending to recover delays. The proposed multi-objective method is able to provide good solutions to the rescheduling problem and over-performs the simple strategy in most cases, with an acceptable process time. We conclude with interesting perspectives for future work.
2

Roslagsbanan: A capacity comparison between the current ATC system and the implementation of a CBTC system

Sofroniou, Chrysostomos January 2021 (has links)
Communications-based train control (CBTC) aims to improve headways in the railway systems while maintaining or even improving safety. By means of the CBTC systems, the exact position of a train is known more accurately than the traditional signalling systems. It is a continuous, automatic train control system utilizing high-resolution train location determination, independent from track circuits. The system makes use of the telecommunications between the train and track equipment for the traffic management and infrastructure control. Roslagsbanan is a narrow gauge urban railway system that connects Stockholm with the northern suburbs of the city and despite its age and limited capacity, it is one of the most used railways in Sweden. From the beginning, the entire track consisted of single-tracks where the trains had to wait for each other on special meeting tracks. Αn expansion plan is now underway and the authorities are building approximately 22 km of double-track where the trains will be able to meet. All work along the Roslagsbanan aims to increase capacity, safety and accessibility. With more double-tracks and an updated signal system, the risk of traffic disruptions will be reduced and it is possible to have more frequent traffic in the future. This master’s thesis investigates a CBTC implementation in Roslagsbanan according to the current expansion plan and comparisons are conducted between the current capacity of the ATC system. A simulation model is developed that calculates the train’s safe braking curve and safe braking distance and two case studies are examined. The first one: Calculation of the capacity of the train routes and examination a capacity increase by a minimum 20% during rush hour, taking into consideration the current expansion plan in double-tracks. The second one: Calculation of the capacity of the train routes considering double-tracks the entire route. In this way, differences could be seen between the traffic density with single and double-tracks. Several insights were gained during the realization of this project and as well as timetables have been created to visualize the findings of this thesis. The timetable’s regularity time is decreased to a significant degree and more frequent traffic can be accommodated. Furthermore, the capacity is definitely affected by the track/infrastructure design however, it is questionable whether this increase in capacity outweighs the economic factor of expanding the entire route to double-tracks. / Kommunikationsbaserad tågkontroll (CBTC) syftar till att förbättra framsteg i järnvägssystemen samtidigt som säkerheten bibehålls eller till och med förbättras. Med hjälp av CBTC-systemen är ett tågs exakta position känd mer exakt än de traditionella signalsystemen. Det är ett kontinuerligt, automatiskt tågkontrollsystem som använder högupplöst tåglägesbestämning, oberoende av spårledning. Systemet använder telekommunikation mellan tåg och spårutrustning för trafikledning och infrastrukturkontroll. Roslagsbanan är ett smalspårigt stadsjärnvägssystem som förbinder Stockholm med stadens norra förorter och trots sin ålder och begränsade kapacitet är det en av de mest använda järnvägarna i Sverige. Från början bestod hela spåret av enkelspår där tågen fick vänta på varandra på speciella mötesstationer. Ett utvecklingsprogram pågår nu och myndigheterna bygger cirka 22 km dubbelspår där tågen kommer att kunna mötas. Allt arbete längs Roslagsbanan syftar till att öka kapacitet, säkerhet och tillgänglighet. Med fler dubbelspår och ett uppdaterat signalsystem minskar risken för trafikstörningar och det är möjligt att ha mer frekvent trafik i framtiden. Detta examensarbete undersöker ett CBTC-genomförande i Roslagsbanan enligt den nuvarande expansionsplanen och jämförelser görs med ATC-systemets nuvarande kapacitet. En simuleringsmodell har utvecklats som beräknar tågets säkra bromskurva och säkra bromssträcka och två fallstudier undersöks. Den första: Beräkning av tåglinjernas kapacitet och undersökning av en kapacitetsökning med minst 20% under rusningstid med hänsyn till den nuvarande expansionsplanen i dubbelspår. Den andra: Beräkning av tåglinjernas kapacitet med tanke på dubbelspår hela rutten. På detta sätt kunde skillnader ses mellan trafiktätheten med enkel- och dubbelspår. Flera insikter gjordes under genomförandet av detta projekt och tidtabeller har skapats för att visualisera resultaten av denna avhandling. Tiden mellan tågen minskas i betydande grad och mer frekvent trafik kan tillgodoses. Dessutom påverkas kapaciteten definitivt av ban-/infrastrukturutformningen, men det är tveksamt om denna kapacitetsökning uppväger den ekonomiska faktorn att utöka hela rutten till dubbelspår.
3

Efficient driving of CBTC ATO operated trains

Carvajal Carreño, William January 2017 (has links)
Energy consumption reduction is one of the priorities of metro operators, due to financial cost and environmental impact. The new signalling system Communications-Based Train Control (CBTC) is being installed in new and upgraded metro lines to increase transportation capacity. But its continuous communication feature also permits to improve the energy performance of traffic operation, by updating the control command of the Automatic Train Operation (ATO) system at any point of the route. The present research addresses two main topics. The first is the design of efficient CBTC speed profiles for undisturbed train trajectory between two stations. The second takes into account the interaction between two consecutive trains under abnormal traffic conditions and proposes a tracking algorithm to save energy. In the first part of the research an off-line methodology to design optimal speed profiles for CBTC-ATO controlled trains is proposed. The methodology is based on a new multi-objective optimisation algorithm named NSGA-II-F, which is used to design speed profiles in such a way that can cover all the possible efficient solutions in a pseudo-Pareto front. The pseudo–Pareto front is built by using dominated solutions to make available a complete set of feasible situations in a driving scenario. The uncertainty in the passenger load is modelled as a fuzzy parameter. Each of the resulting speed profiles is obtained as a set of parameters that can be sent to the ATO equipment to perform the driving during the operation. The proposed optimisation algorithm makes use of detailed simulation of the train motion. Therefore, a simulator of the train motion has been developed, including detailed model of the specific ATO equipment, the ATP constraints, the traction equipment, the train dynamics and the track. A subsequent analysis considers the effect in the design of considering the regenerative energy flow between the train and the surrounding railway system. The second part of the research is focused on the proposal and validation of a fuzzy tracking algorithm for controlling the motion of two consecutive trains during disturbed conditions. A disturbed condition is understood as a change in the nominal driving command of a leading train and its consequences in the subsequent trains. When a train runs close enough to the preceding one, a tracking algorithm is triggered to control the distance between both trains. The following train receives the LMA (limit of movement authority) via radio, which is updated periodically as the preceding train runs. The aim of the proposed algorithm is to take actions in such a way that the following train could track the leading train meeting the safety requirements and applying an energy saving driving technique (coasting command). The uncertainty in the variations of the speed of the preceding train is modelled as a fuzzy quantity. The proposed algorithm is based on the application of coasting commands when possible, substituting traction/braking cycles by traction/coasting cycles, and hence saving energy. Both algorithms were tested and validated by using a detailed simulation program. The NSGA-II-F algorithm provided additional energy savings when compared to fixed block distance-to-go configurations, and giving a more even distribution of the solutions. The fuzzy tracking algorithm provides energy savings with a minor impact on running times while improving comfort, because of the reduction of the inefficient traction/braking cycles. / <p>QC 20170216</p>

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