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International audience; Ce projet est né à la suite d'échanges au sein du groupe de travail « Retour d'expérience technique » de l'IMdR piloté par N. Dechy (IRSN) et E. Rémy (EDF), et à l'initiative de A. Lannoy (IMdR) à la suite du constat d'une démocratisation des nouvelles technologies liées au « digital » ayant bouleversé les méthodes traditionnelles de création de valeur des entreprises.

International audience; Cette communication a pour objectif de déplacer le regard de la sécurité réglée et gérée vers un processus de sécurisation des actions.

International audience; Ce papier propose quelques solutions pour introduire un niveau de sécurité suffisant sur des technologies de reconnaissance d'image à base de d'I.A. dans une application de signalisation ferroviaire.

International audience; L'arrivée des métros sans conducteurs s'accompagne de changements dans la gestion des risques d'indisponibilité. Ces évolutions mettent en évidence la nécessité de maîtriser tous les points critiques, d'un point de vue de la disponibilité, de ces systèmes ferroviaires complexes. Mots clés-métros sans conducteurs, systèmes ferroviaires complexes, points critiques, disponibilité

International audience; Management of a multimodal transport network is a challenging task and operators regularly have to deal with different types of disturbances that affect the quality of service of the transport system. To support them in their decision-making, we present the architecture of a multimodal supervision system that implements monitoring, prediction of affluence, disturbances, impacts and evaluation of functionalities focusing on one or multiples lines of the network. Our system uses the real-time data of transport operators to compute several key performance indicators (KPI) in order to monitor the network status and to detect disturbances. The prediction function is used to predict passengers' attendance at stations, incident duration and the evolution of the whole network, in particular, phenomena emerging from the interconnections linked to the affected line. Finally, we present a use case of the supervision system applied to a real-time control of a bus line belonging to a very dense and busy segment of the multimodal transport network in Ile-de-France area.

International audience; To check the correctness of heterogeneous models of a complex critical system is challenging to meet the certification standard. Such guarantee can be provided by embedding the heterogeneous models into an integrated modelling framework. This work is proposed in the B-PERFect project of RATP (Parisian Public Transport Operator and Maintainer), it aims to apply formal verification using the PERF approach on the integrated safety-critical software related to railway domain expressed in a single modelling language: HLL. This paper presents a certified translation from B formal language to HLL. The proposed approach uses HOL as a unified logical framework to describe the formal semantics and to formalize the translation relation of both languages. The developed Isabelle/HOL models are proved in order to guarantee the correctness of our translation process. Moreover, we have also used weak-bisimulation relation to check the correctness of translation steps. The overall approach is illustrated through a case study issued from a railway software system: onboard localization function. Furthermore, it discusses the integrated verification at the system level.

International audience

International audience; Summary RATP is developing a safety policy allowing it to protect itself from the hazard events. For almost fifteen years, the RATP's precursor of hazards analysis of railway networks has been used to monitor railway safety events on a monthly basis using a specific statistical analysis model. The objective of the paper is to present the prediction algorithm developed to estimate the occurrences of each precursor monitored for the next month. These estimates will be based on a probabilistic modeling of precursors that will take into account their past behavior, certain contextual variables and monthly recommendations issued by RATP.; La RATP développe une politique de sécurité lui permettant de se prémunir des événements redoutés. Depuis près de quinze ans, l'analyse des précurseurs de dangers des réseaux ferroviaires de la RATP, permet de suivre mensuellement les événements relatifs à la sécurité ferroviaire suivant un modèle d'analyse statistique spécifique. L'objectif de la communication est de présenter l'algorithme de prévision développé permettant d'estimer les occurrences de chaque précurseur suivi pour le prochain mois. Ces estimations reposeront sur une modélisation probabiliste des précurseurs qui tiendra compte du comportement passé de ces derniers, de certaines variables contextuelles et des recommandations mensuelles émises par la RATP.

International audience; Summary The aim of this risk management process is to integrate cyber threats in addition to recognised railway safety analysis. The method consists of 5 modules : Context, Sources of threat characterization, Strategic scenarios analysis, Operational scenarios analysis and Defence system specification. A complete and practical case study has been performed on a CBTC GOA4. The results are conclusive and so the RATP wants to generalise this process to the overall concerned systems.; Cette démarche de maîtrise des risques a été élaborée dans le but d'intégrer les exigences liées aux cyber-menaces dans le processus de construction de la sécurité ferroviaire qui est reconnu actuellement. La méthode se décompose en 5 modules : Contexte, Caractérisation des sources de menace, Analyse des scénarios stratégiques, Analyse des scénarios opérationnels et Spécification du système de défense. Un cas pratique de mise en oeuvre réelle et complète de la méthode a été réalisé sur un CBTC GOA4.Le résultat a été jugé concluant et la RATP souhaite généraliser cette démarche sur l'ensemble des systèmes concernés.

International audience; Summary RATP is developing a safety policy allowing it to protect itself from the hazard events. For almost fifteen years, the RATP's precursor of hazards analysis of railway networks has been used to monitor railway safety events on a monthly basis using a specific statistical analysis model. The objective of the paper is to present the prediction algorithm developed to estimate the occurrences of each precursor monitored for the next month. These estimates will be based on a probabilistic modeling of precursors that will take into account their past behavior, certain contextual variables and monthly recommendations issued by RATP.; La RATP développe une politique de sécurité lui permettant de se prémunir des événements redoutés. Depuis près de quinze ans, l'analyse des précurseurs de dangers des réseaux ferroviaires de la RATP, permet de suivre mensuellement les événements relatifs à la sécurité ferroviaire suivant un modèle d'analyse statistique spécifique. L'objectif de la communication est de présenter l'algorithme de prévision développé permettant d'estimer les occurrences de chaque précurseur suivi pour le prochain mois. Ces estimations reposeront sur une modélisation probabiliste des précurseurs qui tiendra compte du comportement passé de ces derniers, de certaines variables contextuelles et des recommandations mensuelles émises par la RATP.

International audience; Summary The aim of this risk management process is to integrate cyber threats in addition to recognised railway safety analysis. The method consists of 5 modules : Context, Sources of threat characterization, Strategic scenarios analysis, Operational scenarios analysis and Defence system specification. A complete and practical case study has been performed on a CBTC GOA4. The results are conclusive and so the RATP wants to generalise this process to the overall concerned systems.; Cette démarche de maîtrise des risques a été élaborée dans le but d'intégrer les exigences liées aux cyber-menaces dans le processus de construction de la sécurité ferroviaire qui est reconnu actuellement. La méthode se décompose en 5 modules : Contexte, Caractérisation des sources de menace, Analyse des scénarios stratégiques, Analyse des scénarios opérationnels et Spécification du système de défense. Un cas pratique de mise en oeuvre réelle et complète de la méthode a été réalisé sur un CBTC GOA4.Le résultat a été jugé concluant et la RATP souhaite généraliser cette démarche sur l'ensemble des systèmes concernés.

International audience

International audience

International audience; Summary A comprehensive framework for influence operations is developed consisting of a taxonomy of influence principles, an analysis of a target audience's cognitive map and a set of dynamic patterns to build effects-based courses of action.; Nous présentons un cadre complet de modélisation des opérations d'influence, composé d'une taxonomie des principes d'influence, d'une cartographie cognitive des audiences-cibles et d'un ensemble de modes d'action pour développer des scénarios selon l'effet final recherché. Nous étudions ensuite l'application de ce modèle au cyberespace et nous réfléchissons aux éléments possibles d'une stratégie de défense.

This RATP document, based on an original document from Prover Technology, details the syntax and semantics of the formal modelling language " High Level Language " (HLL).HLL is used for several years by RATP to perform formal verification on CBTC and interlocking safety critical software.; Ce document RATP, basé sur un document original de Prover Technology, détaille la syntaxe ainsi que la sémantique du langage de modélisation formelle HLL (pour High Level Language).HLL est utilisé depuis plusieurs années maintenant à la RATP pour réaliser des vérifications formelles sur les logiciels critiques des CBTC et postes de signalisation.

Musculoskeletal disorders (MSDs) are the cause of a very high loss ratio and companies sometimes feel helpless when faced with this issue. There is a great temptation to direct prevention efforts towards an individual approach. Companies are frequently approached by external stakeholders who propose to set up warm-up and stretching programs, muscle-strengthening exercises... to prevent the onset of MSDs. These practices raise many questions. After an overview of the various proposed techniques, a literature review analyzes their relevance and their place in MSDs prevention. Finally, points of reference on the conditions for their implementation are also presented., Les troubles musculosquelettiques (TMS) sont à l'origine d'une sinistralité très élevée et les entreprises se sentent parfois démunies face à ce problème. La tentation est grande aujourd'hui d'orienter les efforts de prévention vers une approche individuelle. Les entreprises sont très fréquemment sollicitées par des intervenants extérieurs qui leur proposent d'instaurer des programmes d'échauffements, d'étirements, d'exercices de renforcement musculaire… en vue de prévenir l'apparition des TMS. Ces pratiques posent de nombreuses questions. Après un état des lieux des différentes techniques proposées, une revue de la littérature analyse leur pertinence et leur place dans la prévention des TMS. Enfin, des points de repères sur les conditions de leur mise en œuvre sont également présentés.

International audience; An independent safety assessment of railway software systems is performed by RATP (Régie Autonome des Transports Parisiens) for all safety-critical systems before their deployment in its network. Whenever possible, this activity is performed using the PERF approach (Proof Executed over a Retro-engineered Formal model). PERF is a methodology which handles formal verification of already developed software. This approach is applied to a variety of software systems, developed using languages such as SCADE, Ada or C. It provides an alternative verification that can be applied for the independent safety assessment of critical systems used by RATP. In this paper, we propose the B-PERFect method to generalize the application of the PERF approach for critical systems which are based on the B method. In particular, this paper focuses on transformation strategy from B language to the pivot language of PERF: HLL. HLL is a synchronous data-flow language equipped with formal verification techniques. The differences between B and HLL are pointed out and the translation process is presented in this regard.

In this article we propose a methodology helping RATP (public transport operator) experts to analyze railway big amount of data. Indeed, a huge number of data can rapidly lead to focus on wrong analysis. We developed a tool prototype based on visual analytics process that can display an overview of a selected railway network area. This overview deals with one or several operating days of the same railway line. The operator chooses statistical indicators to obtain a suitable view display for his specific study. This process is the first part of our work which will model the human driver pattern using machine learning and data mining. Our work methodology is based on Visual analytics process.

This paper presents an approach developed to study the behavior of the masonry vaulted tunnels in order to evaluate the serviceability state and failure load. An appropriate homogenization technique is used to simulate the global anisotropic behavior across the vault. The model takes into account isotropic damage in each component of the masonry and the variations of the directions of anisotropy in case of a vault. A set of comparisons with experimental tests allowed the validation of the proposed approach. Failure loads and deformation states are correctly assessed. The present model was programmed in the finite element code CESAR-LCPC.; Cet article présente une approche développée pour étudier le comportement des voutes de tunnels en maçonnerie pour évaluer leurs états limites de service et ultimes. Une technique d'homogénéisation appropriée est utilisée pour simuler le comportement anisotrope global de la voute. Le modèle prend en compte l'endommagement de chaque composant de la maçonnerie et les variations des directions d'anisotropie dans le cas d'une voute. Un ensemble de comparaisons avec des résultats expérimentaux permet de valider l'approche proposée. Les charges limites et les déformations sont correctement reproduites. Le modèle a été introduit dans le code de calcul par éléments finis CESAR-LCPC.

International audience; This paper describes the construction of a stochastic model of urban railway track geometry irregularities, based on experimental data. The considered irregularities are track gauge, su-perelevation, horizontal and vertical curvatures. They are modelled as random fields whose statistical properties are extracted from a large set of on-track measurements of the geometry of an urban railway network. About 300 to 1000 terms are used in the Karhunen-Lò eve/Polynomial Chaos expansions to represent the random fields with appropriate accuracy. The construction of the random fields is then validated by comparing on-track measurements of the contact forces and numerical dynamics simulations for different operational conditions (train velocity and car load) and horizontal layouts (alignment, curve). The dynamics simulations are performed both with and without randomly generated geometrical irregularities for the track. The power spectrum densities obtained from the dynamics simulations with the model of geometrical irregularities compare extremely well with those obtained from the experimental contact forces. Without irregularities, the spectrum is 10 to 50 dB too low.

International audience; Rail squats remain a major rolling contact fatigue problem for mass transit authorities. Several studies have been conducted to supplement the standard characterization of rail squats. In particular an extensive tribological and metallurgical investigation was performed on samples of incipient squats from various areas. Surfaces and cross-sections of rail samples were observed by optical microscopy and scanning electron microscopy. These observations highlighted that the running band is composed of longitudinal contact strips with various surface and subsurface morphologies. This microstructure seems to be essential for the onset of squats. This new information makes it possible to account for the entire damage mechanism of a squat defect from initiation to propagation.

International audience

International audience

A stochastic model of the geometry of the RATP Regional Express Network line A (RERA) is here proposed. The track irregularities are modelled as random fields whose features are deduced from processed measurement data. The versines measurements are deconvolved to obtain the curvatures taking into account the circulation direction of the train and estimating the signalto-noise ratio. Then, the Karhunen-Loeve expansion is used to capture the spatial correlation and the Polynomial Chaos expansion ensures a good statistical variability of the track geometry. At the end, this model allows to capture the spatial and statistical variability of the track geometry of the considered railway network. Using this model it is possible to generate realistic track geometries, which are representative of the whole network.

International audience

In order to predict the lifetime of railtrack components, numerical models are required to better describe the apparition of microstructural defects that lead to material failure. In pearlitic steels, the severe mechanical loading or/and the local temperature increase result in the formation of a hard and brittle phase that is prone to cracking, which is called White Etching Layer (WEL). The current study proposes a phenomenological model, based on the microstructural evolution, to describe the mechanically-induced-WEL kinetics of formation. First, a detailed multiscale microstructural characterization was performed in order to identify suitable microstructural indicators for the WEL formation. The grain size, orientation and morphology, and internal disorientation were characterized for different steps of mechanical WEL formation. This could be achieved thanks to the use of a dedicated test bench that allows to monitor the wheel–rail contact condition (sliding, number of cycles, and contact pressure) independently. The proposed model was validated using tests performed in extreme load and sliding conditions. The numerical and experimental results indicate that the most severe conditions (contact pressure and sliding ratio) catalyze WEL formation, and that the same deformation state can be achieved through different loading paths. This work is part of the multi-disciplinary project MOPHAB, which aims to improve our knowledge and understanding of the mechanisms leading to the formation of the white etching layer in the materials used to construct railways and to develop corresponding numerical models. This project was supported by IRT Railenium and other industrial partners (RATP: Régie Autonome des Transports Parisiens, France, SNCF: Société Nationale des Chemins de Fer Francais, France, SAARSTAHL rail).

International audience; A simulation-based model used to measure resilience indicators of the railway transportation system is presented. This model is tested through a perturbation scenario: the inoperability of a track which links two stations in the system. The performance of the system is modelled through two indicators: (a) the number of passengers that reach their destination and (b) the total delay of passengers after a serious perturbation. The number of passengers within a given station at a given time is considered as early warning in the model. Furthermore, a crisis management plan has been simulated for this perturbation scenario in order to help the system to recover quickly from this perturbation. This crisis management plan emphasizes the role and the importance of the proposed indicators when managing crises.

International audience; This chapter presents the proof process used by Thales and Autonomous Operator of Parisian Transports (RATP) to demonstrate the safety of the signaling systems used for the RATP network in Paris. It introduces the rail application concerned by the author's proof activities, the Thales system used for the metro. The chapter then presents the models used in the formal proof process, before describing the proof suite designed by Prover Technology. The results of application of the proof process to the Thales signaling system for RATP line are described and discussed in detail, before considering a number of potential improvements. The chapter presents a brief overview of the architecture of the PMI system. It discusses the computerized interlocking module (CIM) subsystem, which constitutes the operational core of the signaling system

International audience

Cet article introduit une approche generique nommee VirMaLab (pour atelier virtuel de maintenance) permettant de developper des modeles de maintenance, basee sur la fiabilite, de systemes multicomposants et multietats. S’appuyant sur le formalisme des modeles graphiques probabilistes (MGP) [ou reseaux bayesiens (RB)], cette approche stochastique modelise aussi bien les processus de degradation caracterisant le systeme etudie (une approche semimarkovienne originale sera proposee pour cela) que les procedures de diagnostic mises en oeuvre et les actions de maintenance qui en decoulent. L’integration de couts (d’exploitation, d’indisponibilite, de maintenance…) est egalement possible. A titre d’illustration, deux applications de cette demarche sont introduites, dediees a la maintenance du rail. La premiere s’interesse a l’optimisation du compromis regeneration/reparation pour le troncon central du RER A, tandis que la seconde vise a permettre l’evaluation et la comparaison de differentes strategies de maintenance pour la prevention de la rupture du rail dans un contexte de modernisation des automatismes de lignes a roulement fer du metro parisien.

The formation of a white etching layer (WEL), a very hard and brittle phase on the rail surface, is associated with a progressive transformation of the pearlitic grain to very fragmented grains due to the cumulative passage of trains. Its formation is associated with a complex thermomechanical coupling. To predict the exact conditions of WEL formation, a thermomechanical model previously proposed by the authors needs to be validated. In this study, monotonic and cyclic shear tests using hat-shaped specimens were conducted in the temperature range of 20 C to 400 C to reproduce the WEL formation. The tests showed a strong sensitivity of the material to temperature, which does not necessarily favor WEL formation. For the monotonic tests, no WELs were produced; however, a localization of the plastic deformation was observed for tests performed at 200 C and 300 C. In this temperature range, the material was less ductile than at room temperature, leading to failure before WEL formation. At 400 C, the material exhibited a much more ductile behavior, and nanograins close to WEL stages were visible. For the cyclic tests, a WEL zone was successfully reproduced at room temperature only and confirmed the effect of shear in WEL formation. The same cyclic tests conducted at 200 C and 300 C yielded results consistent with those of the monotonic tests; the deformation was much more localized and did not lead to WEL formation. This work is part of the multi-disciplinary project MOPHAB, which aims to improve our knowledge and understanding of the mechanisms leading to the formation of the white etching layer in the materials used to construct railways and to develop corresponding numerical models. This project was supported by IRT Railenium and other industrial partners (RATP: Régie Autonome des Transports Parisiens, France, SNCF: Société Nationale des Chemins de Fer Francais, France, SAARSTAHL rail).

International audience; This study is composed of three essential parts. The first part describes an indirect semi-experimental method which is used to reconstruct the excitation force of an operating diesel engine from the acceleration data measured at the mounting points. These internal forces can not be directly measured with force sensors; they have to be derived from the dynamic deformation of the engine support, so a theoretical analysis is carried out to derive the equations for the force re-construction.The second part deals with prevention of low frequency vibration of the powertrain from spreading to the rest of the vehicle. Three uncoupling techniques are used to minimize these vibrations. The first technique reduces the non-diagonal elements of stiffness matrix. The second technique uses the elastic axes decoupling criterion. The third technique uncouple the torque roll axis (TRA) by using the previously determined excitation efforts.In the third part, numerical and experimental results are discussed. The solicitations deducted and the positions of mounts allowing decoupling of the powertrain are presented.

La première partie de ce rapport s'articule autour de l'analyse du processus de concertation pour l'aménagement du poste de conduite du Translohr et de l'observation de la conduite d'un tramway "classique" à roulement fer pour déterminer s'il existe des spécificités entre les deux types de tramway. La seconde partie analyse les caractéristiques des lignes T5 et T6 tant du point de vue de leur insertion urbaine que de leur rôle dans les réseaux franciliens.

International audience; The RATP (Paris Public Transport System) needs a software to optimize the passengers' exchanges between the trains and the platforms in order to improve the train frequency and to reduce risks within passengers congestion. The SimTRAP prototype (Simulation of exchanges between TRains And Platforms) is an agent based model, using a microscopic approach, which is being built for this task.

Mise à disposition du document numérique avec l'aimable autorisation de l'éditeur; International audience; Nous proposons pour cette intervention un double regard sur les parcours dans les espaces de transport : celui de sociologue analysant les interactions en espaces publics et celui de chargé de projets en design et projets culturels à la RATP. L'analyse sociologique en action (école de Chicago) portée au cœur des espaces de transport sur les conséquences des projets de design a permis d'identifier une attente majeure vécue par les usagers (enquêtes de terrain/entretiens lors du travail de thèse). Ils espèrent des concepteurs qu'ils prennent en compte de façon systématiquement combinée les compétences fonctionnelles et sensibles des espaces, là où elles sont souvent pensées comme radicalement distinctes. Le déploiement par les savoirs " sensibles " (Architecture, Design...) de vocabulaires attentionnés en espaces publics passe par un travail global de scénographie des lieux, déclinable en fonction des publics. De la construction d'une ambiance à la métamorphose totale des perceptions, se dessine une dynamique de préservation de la vulnérabilité des engagements en espace public. Le trajet envisagé comme récit au sein d'une ville mosaïque s'écrit de manière radicalement différente en fonction de la qualité des affects proposés par les lieux, co-acteurs de la scène. L'action du Design au sein des espaces de transport de la RATP doit-il donc se lire comme une volonté d'échapper au paradigme posé par Hanna Arendt : " vivre avec l'autre, sans autrui " ?

The fourteenth line of the Paris metro (France), called Météor, is currently extended towards Saint-Lazare railway station in a very busy and historic district of Paris. The Transport Company (RATP), as a contracting authority, is then confronted with a complex environment. The constraints have determined works planning and construction methods. In particular, the alluvial deposits were reinforced by injection of microfine cement grout whose fluidity allows to accurately permeate fine soils. It was preferred to more traditional and potentially polluting grouts. After a description of the geotechnical conditions of the site, the different steps of underground constructions are briefly showed. Many control measurements have been integrated to the project to ensure the integrity of the surrounding structures. Grout pressure was thus continually fitted to the heaving of the foundations of sensitive buildings. In situ pressuremeter tests were also carried out before and after grout injection in order to verify the quality of soil improvement. Likewise, triaxial tests were performed on uncemented alluvial deposits and on alluvial deposits grouted in the laboratory. These tests show that the mechanical properties of the alluvial deposits were clearly improved by grouting.

Cette recherche tente d'établir un état de l'art sur la question des méthodes de monétarisation des effets de la pollution atmosphérique en milieu urbain.La démarche adoptée passe par un recensement bibliographique et une analyse détaillée des principales études menées dans le courant des années 90, ainsi que par une réflexion sur les usages des résultats par les pouvoirs publics.Le propos de cette étude est d’amener le lecteur à s’interroger sur les processus qui conduisent à l’élaboration de ces chiffres, d'un point de vue scientifique d’abord (que mesure-t-on, comment, pourquoi ?) et politique ensuite (par quels mécanismes institutionnels les valeurs construites par les chercheurs -ingénieurs, économistes, épidémiologistes, etc.- vont aider à l’élaboration de valeurs “tutélaires”, qui fournissent une base assumée et explicite aux prises de décision dans la gestion des affaires publiques ?).

Le design regroupe des métiers en expansion. Les designers conçoivent des solutions, en matière de produits, de signes, d'espaces, de services ou de systèmes, mais ils sont aussi appelés en amont à structurer le cahier des charges en jouant un rôle de médiateur entre toutes les parties prenantes. Dans la mobilité urbaine, un domaine complexe et systémique, la pertinence du design se renforce. A Lille, lors des manifestations de la World Design Capital en 2020, des expositions, des awards et des conférences ont permis de montrer comment le design oriente l'innovation au service des utilisateurs avant tout

International audience; The human gait program involves many brain areas such as motor cortices, cerebellum, basal ganglia, brainstem, and spinal cord. The mesencephalic locomotor region (MLR), which contains the pedunculopontine (PPN) and cuneiform (CN) nuclei, is thought to be one of the key supraspinal gait generators. In daily life activities, gait primarily occurs in complex conditions, such as through narrow spaces, or while changing direction or performing motor or cognitive tasks. Here, we aim to explore the activity of these subcortical brain areas while walking through narrow spaces, using functional MRI in healthy volunteers and designing a virtual reality task mimicking walking down a hallway, without and with an open doorway to walk through. As a control, we used a virtual moving walkway in the same environment. Twenty healthy volunteers were scanned. Fifteen subjects were selected for second level analysis based on their ability to activate motor cortices. Using the contrast Gait versus Walkway, we found activated clusters in motor cortices, cerebellum, red nucleus, thalamus, and the left MLR including the CN and PPN. Using the contrast Gait with Doorway versus Walkway with Doorway, we found activated clusters in motor cortices, left putamen, left internal pallidum, left substantia nigra, right subthalamic area, and bilateral MLR involving the CN and PPN. Our results suggest that unobstructed gait involves a motor network including the PPN whereas gait through a narrow space requires the additional participation of basal ganglia and bilateral MLR, which may encode environmental cues to adapt locomotion.

Mobil.TUM 2018, International Scientific Conference on Mobility and Transport: Urban Mobility - Shaping the Future Together, MUNICH, ALLEMAGNE, 13-/06/2018 - 14/06/2018; Urban population and mobility needs are rapidly growing while transportation infrastructures are constrained by both limited space and budget allocation. Demand is greater than supply which produces saturation phenomena. Congestion is a major issue impacting the performance of urban transit systems in many ways: operating costs, efficiency and quality of service to name just a few. Regarding rail transit, congestion phenomena are observed in both train and pedestrian traffic. At metro stations, train and pedestrian flows meet and interact with each other. Pedestrian arrivals are pulsed by train arrivals and, inversely, train departures may be delayed because of an excessive number of passengers boarding or/and alighting.The interaction mainly occurs at the platform level where the exchange between passengers is observed.

In this paper we present a mathematical model of the train dynamics in a linear metro line system with demand-dependent run and dwell times. On every segment of the line, we consider two main constraints. The first constraint is on the travel time, which is the sum of run and dwell time. The second one is on the safe separation time, modeling the signaling system, so that only one train can occupy a segment at a time. The dwell and the run times are modeled dynamically, with two control laws. The one on the dwell time makes sure that all the passengers can debark from and embark into the train. The one on the run time ensures train time-headway regularity in the case where perturbations do not exceed a run time margin. We use a Max-plus algebra approach which allows to derive analytic formulas for the train time-headway and frequency depending on the number of trains and on the passenger demand. The analytic formulas, illustrated by 3D figures, permit to understand the phases of the train dynamics of a linear metro line being operated as a transport on demand system., Comment: arXiv preprint, accepted for publication at IEEE American Control Conference, Milwaukee, June 2018

We present here a real-time control model for the train dynamics in a linear metro line system. The model describes the train dynamics taking into account average passenger arrival rates on platforms, including control laws for train dwell and run times, based on the feedback of the train dynamics. The model extends a recently developed Max-plus linear traffic model with demand-dependent dwell times and a run time control. The extension permits the elimination of eventual irregularities on the train time-headway. The resulting train dynamics are interpreted as a dynamic programming system of a stochastic optimal control problem of a Markov chain. The train dynamics still admit a stable stationary regime with a unique average growth rate interpreted as the asymptotic average train time-headway. Moreover, beyond the transient regime of the train dynamics, our extension guarantees uniformity in time of the train time-headways at every platform., Version updated on 29/10/2018, index error corrected. arXiv preprint, to appear in Proceedings of the 2018 IEEE Intelligent Transportation Systems Conference, Maui/Hawaii

A significant proportion of the Paris metro tunnels comprise a masonry vault built out of stone blocks and mortar joints, and sidewalls and slabs made of unreinforced concrete. In order to provide the necessary data for future structural evaluation, an extensive laboratory testing programme has been conducted to characterize the materials of the tunnel separately, i.e., mortar, stone, and concrete. The tests, carried out on specimens taken from cores extracted from a 1930s tunnel, enabled to determine the mechanical properties, including direct tensile, shear strength, and mode I fracture energy, as well as the properties of the stone-mortar interface. Results show that the masonry mortar joints could reach 10 cm in width, and that blocks of stone varied in composition and porosity, thus producing a wide range of mechanical properties. The concrete was composed of large-sized aggregates and showed low stiffness and strength. Based on these experimental results, ratios between mechanical characteristics are hereby proposed. Perspectives on the use of this experimental data in a finite element model are then discussed.

International audience; This paper investigates the effects of the track geometry irregularities on the wheel-rail dynamic interactions and the rail fatigue initiation through the application of the Dang Van criterion, that supposes an elastic shakedown of the structure. The irregularities are modelled , using experimental data, as a stochastic field which is representative of the considered railway network. The tracks thus generated are introduced as the input of a railway dynamics software to characterize the stochastic contact patch and the parameters on which it depends: contact forces and wheelset-rail relative position. A variance-based global sensitivity analysis is performed on quantities of interest representative of the dynamic behaviour of the system, with respect to the stochastic geometry irregularities and for different curve radius classes and operating conditions. The estimation of the internal stresses and the fatigue index being more time-consuming than the dynamical simulations, the sensitivity analysis is performed through a metamodel, whose input parameters are the wheel-rail relative position and velocity. The coefficient of variation of the number of fatigue cycles, when the simulations are performed with random geometry irregularities, varies between 0.13 and 0.28. In a large radius curve, the most influent irregularity is the horizontal curvature, while, in a tight curve, the gauge becomes more important.

CDC 2017, IEEE Conference on Decision and Control, Melbourne, AUSTRALIE, 12-/12/2017 - 15/12/2017; This paper presents a predictive model for the train dynamics on a mass-transit metro line with one symmetrically operated junction. We distinguish three parts: a central part and two branches. The tracks are spatially discretized into segments (or blocks) and the train dynamics are described by a discrete event system where the variables are the kth departure times from each segment. The train dynamics are based on two main constraints: a travel time constraint modeling theoretic run and dwell times, and a safe separation constraint modeling the signaling system in case where the traffic gets very dense. The Max-plus algebra model allows to analytically derive the asymptotic average train frequency as a function of many parameters, including train travel times, minimum safety intervals, the total number of trains on the line and the number of trains on each branch. This derivation permits to understand the physics of traffic. In a further step, the results will be used for traffic control.

Le projet NEWTUN apporte une série de résultats innovants, aux perspectives de développement trèsintéressantes à court terme et moyen terme avec le démarrage des travaux du Grand Paris.Grâce aux travaux de NEWTUN, la robotisation est en passe d’être introduite dans l’univers de la petiteperforation, et plus largement dans celui des fondations spéciales. Il convient ici de remercier les partenaires du projet, qui ont su mener toutes ces recherches de frontdans un excellent esprit de coopération ; ce climat a permis de tirer le meilleur parti des synergiesoffertes par les compétences très diversifiées du consortium.Nos remerciements tout particuliers s’adressent aux organismes financeurs du projet, sans qui le projetNEWTUN n’aurait tout simplement pas eu lieu :- La Banque Publique d’Investissement,- Le Conseil Général des Yvelines (78),- Le Conseil Général du Département de la Seine et Marne (77).Enfin, nous tenons à mentionner l’appui amical et efficace du Pôle ADVANCITY pour leur assistance au montage du projet.

Reliability analysis has become an integral part of system design and operation. This is especially true for systems performing critical tasks, such as mass transportation systems. This explains the numerous advances in the field of reliability modeling. More recently, some studies involving the use of Bayesian networks have been proven relevant to represent complex systems and perform reliability studies. In previous works, a generic methodology was introduced for developing a decision support tool to evaluate complex systems maintenance strategies. This article deals with development of such a decision tool dedicated to the maintenance of Paris metro rails. Indeed, owing to fulfillment of high-performance levels of safety and availability (the latter being especially critical at peak hours), operators need to estimate, hour by hour their ability to prevent or to detect broken rails. To address this problem, a decision support tool was developed, the aim of this article is to evaluate, compare and optimize various operating and maintenance strategies.