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Simon S.,CNRS Contacts and Structural Mechanics Laboratory | Saulot A.,CNRS Contacts and Structural Mechanics Laboratory | Dayot C.,CNRS Contacts and Structural Mechanics Laboratory | Quost X.,Regie Autonome des Transports Parisiens RATP | Berthier Y.,CNRS Contacts and Structural Mechanics Laboratory
Wear | Year: 2013

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. © 2012 Elsevier B.V.

Vargolici O.,INSA Lyon | Merino P.,INSA Lyon | Saulot A.,INSA Lyon | Ville F.,INSA Lyon | And 3 more authors.
CM 2015 - 10th International Conference on Contact Mechanics of Wheel / Rail Systems | Year: 2015

Under rolling with sliding conditions without lubrication (dry contact), white-etching layers (WEL) develop on the surface of contacting bodies. Mainly attributed to temperature increase, it has been proven that WELs could develop under mechanical conditions, for example in wheel-rail contact [2]. Nevertheless, such mechanical conditions haven't actually been accurately reproduced on tribometers and compared to WELs' reality. To compensate for this lack, tribological tests were performed on a twin-disc machine, under dry sliding conditions. Samples were machined from R260 pearlitic steel rail. Tests parameters were set as close as possible to the wheel-rail contact reality. In order to analyze the influence of the initial surface state on WELs formation, the samples were oxidized or run-in. For oxidized testing, samples were immersed in water saturated with salt for 24h before testing. Observations were made with both optical and electronic microscope, after cutting, polishing and etching with 4% Nital. As previous tests on non-treated samples showed significant wear and particle detachment, a protective layer is created on the surface. The layer of oxide or hardened steel gives time to allow the subsurface to transform, thus helping WELs develop. This "tribological fuse effect" prevents particles from detaching during the entire test, i.e. up to 20 000 cycles.

Adjetey-Bahun K.,Regie Autonome des Transports Parisiens RATP | Birregah B.,University of Technology of Troyes | Chatelet E.,French National Center for Scientific Research | Planchet J.-L.,RATP | Laurens-Fonseca E.,RATP
ISCRAM 2014 Conference Proceedings - 11th International Conference on Information Systems for Crisis Response and Management | Year: 2014

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.

Regie Autonome Des Transports Parisiens Ratp | Date: 2012-11-06

Scientific, surveying, photographic, cinematographic, optical, weighing, measuring, signaling, checking, supervision, life-saving and teaching apparatus and instruments, namely, surveying instruments, cameras, electrical and optical cables, scales, laser measuring systems, railway signals, vehicle traffic signals, traffic control equipment, namely, actuated and pretimed traffic signal controllers, life saving rafts; apparatus and instruments for the supply, distribution, transformation, accumulation, regulation or control of electric current, namely, electricity adapters, electric cables, electric accumulators, electric converters, electric meters; apparatus for recording, transmission or reproduction of sound or images; automatic ticket dispensers; video cameras, electric monitoring apparatus, namely, digital signage monitors, battery monitors, alarm monitoring systems; magnetic cards, namely, magnetic coded gift cards and magnetic identifying cards; blank magnetic data carriers; electric converters; luminous or mechanical signs; electric door openers; electro-dynamic apparatus for the remote control of railway points, electric installations for the remote control of industrial operations, electric control panels; magnet; gramophone records featuring transport and traffic information; automatic vending machines; mechanisms for coin-operated apparatus; cash registers, calculating machines, data processing equipment and computers; computer software for operating public transport systems; computer software in the form of cellular phone applications for the provision of transport information, namely, provision of online itineraries and schedules, real-time traffic updates, interactive maps; computer programs for word processing and for operating public transport systems; computer chips; radio sets; telephone apparatus; video displays, namely, head-mounted video displays and video displays that can be worn on the body. Vehicles, namely, passenger trains, trams, streetcars, subway cars, rail cars, buses, bicycles and motorcycles. Building construction, construction relating to transport, namely, construction of roads, bridges and railway tracks; construction of tunnels and highway interchanges; motor vehicle maintenance and repair; maintenance and repair of rolling stock and fixed equipment for railways and railway signal equipment; installation of public transport networks, signage, payment processing machines, subway platforms, tramway platforms, bus platforms, railroad tracks. Telecommunications services, namely, telecommunication access services, providing electronic telecommunication connections, providing electronic message alerts via the Internet; telecommunication services, namely, electronic bulletin board services; information about telecommunication; rental of telecommunications equipment and apparatus; electronic mail, online services, namely, message sending, communications by computer terminals; providing telecommunications connections to a world-wide computer network. Transport by train, tram, streetcar, subway and bus; information relating to transportation, namely, provision of transport itineraries and schedules, real-time traffic updates and maps; public transport, namely, transport by train, tram, streetcar, subway and bus; packaging of goods for transport; storage of goods; travel and excursion arrangement, arranging of transport; technical management of platforms and transport, namely, management of vehicular and pedestrian traffic flow through advanced communications networks and technology. Education, namely, providing classes and workshops in the field of public transport, urban planning, and sustainable development; providing of training, in the field of public transport, urban planning, and sustainable development; entertainment services, namely, organizing live musical performances and sporting competition activities; organizing community sporting and cultural events; organization of exhibitions for cultural or educational purposes, organization of sports competitions; organization of cultural shows, arranging and conducting of training workshops, colloquiums, conferences and seminars in the field of public transport, urban planning and sustainable development. Scientific and technological services, namely, conducting feasibility studies relating to transport, and research and design relating thereto; industrial research services in the field of public transportation; design and development of computer hardware and software in the field of public transportation; development and design of computer software; computer programming, duplication of computer programs; research in the field of environmental protection, research and development of new products for others; technical research in the field of public transportation; urban and transit planning; construction drafting.

Larcher M.,European Commission - Joint Research Center Ispra | Casadei F.,European Commission - Joint Research Center Ispra | Giannopoulos G.,European Commission - Joint Research Center Ispra | Solomos G.,European Commission - Joint Research Center Ispra | And 2 more authors.
Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit | Year: 2011

Land mass transport systems have an open architecture and are vulnerable to terrorist attacks. In case of an explosion inside trains or stations, the risk of injuries and fatalities may be mitigated by properly strengthening and optimizing these structures. This risk depends on the peak overpressure and impulse, which are estimated here using numerical simulations, and is determined by special probit functions using the pressure-time curve calculated at each fluid point. The geometry of the structures investigated is obtained using a three-dimensional laserscanning technology. Fluid-structure interaction (FSI) calculations have been performed, and for long, tube-like trains channelling effects have been considered. Several materials are used to describe the structural part of the models. A special FSI technique is presented, whereby a structure can be embedded in a fluid mesh without connection to the fluid nodes. This procedure avoids problems after the element erosion due to failure of the structure, e.g. of the glass. The results of case studies are shown in terms of structural displacements and the risk inside a metro line station, a train carriage, and a long train. The effects of venting areas, internal obstacles, such as seats, and passengers themselves to the air blast wave and the associated risk are examined and assessed. © Authors 2011.

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