Browse Topic: High-speed rail systems

Items (34)
Interior Noise Design of a Light Rail Vehicle Using Statistical Energy Analysis2015-01-23006/15/2015
This paper addresses the NVH design of a light rail vehicle whose maximum allowable interior SPL levels at certain speeds are regulated and may vary between countries, states, and cities. The objective of this study was to predict sound pressure levels (SPL) at several interior locations across a wide range of frequencies and estimate if the current design configuration will meet the noise level limits. Statistical Energy Analysis (SEA) was used to predict interior SPL and to understand and rank the various noise contribution paths and give a better understanding of the physics of transmission and what types of design changes are most effective to reduce the overall interior SPL to meet targets. A typical light rail vehicle is composed of a frame-like structure covered by lightweight panels and with interior panels that are increasingly made from composites, sandwich, laminated, or honeycomb materials or extruded panels. These lightweight structures made from materials that have previously been used primarily in aerospace applications have modal characteristics and transmission properties that require more advanced modeling than for simpler monolithic panels. Evaluation of the dominant noise transmission paths from the dominant sources allows sensitivity studies to evaluate which noise paths are the best candidates for improvement to overall vehicle NVH and which parts may be candidates for cost and weight reduction without significant degradation of the acoustic performance. This paper describes the motivation for this study and the details of the light rail vehicle construction. The SEA modeling approach is discussed, including the modeling of the structures and the main contributing sources. The contribution path ranking and the interior SPL predicted by the SEA model at several target locations are presented and compared to measured interior SPL data. Conclusions about the results and recommendations for future work are given.
Fiedler, RobertMusser, ChadwyckCuchý, Petr
Characterisation of the Brake Pads Used in High-Speed Trains2013-01-20289/30/2013
It is essential to characterize the frictional properties of brake pads used in high-speed trains during the processes of development and manufacturing of the pads. This paper presents the test results of new developed composite and powder metallurgical brake pads at different sliding speeds and contact pressures with specially designed test rig. Test results show that the coefficient of friction was increased with the increasing of sliding speed up to 120km/h, but over 120km/h it was decreased with the increasing of sliding speed for the composite brake pads. For the powder metallurgical brake pads, sliding speeds had no significant effect on the friction coefficients of the brake pads. Contact pressure had significant effect on the friction coefficient of brake pads for both materials. Water on the braking contact surfaces had significant effect on the friction coefficient of powder metallurgical brake pads. Temperature had significant effect on the friction coefficient of the powder metallurgical brake pad 2-T5 but had no significant effect on 1-T5. The braking squeal generated from both brake pads of composite material and powder metallurgical material has been investigated. It has been observed that powder metallurgical braking pads were likely to generate squeal but composite brake pads were not. Both sliding speed and contact normal pressure play a significant role on the generation of braking squeal.
Wang, ShuwenZhang, Jing-MingYang, ZhenningChen, Kang
Brazilian Freight Rail Sector - An Overview of Experiences and Perspectives of Concession Model2012-36-021310/2/2012
Brazilian Freight Rail Sector emerged in the end of 19th century, when the first railways were constructed, under the first known grant system in the country. Later, in the beginning of 20th century, rail system was expanded to support the increasing economical activity related to the agroexportation business, specially coffee crops. This not planned process resulted in a non-integrated network that has undermined the economical feasibility of rail system and bankruptcy of some rail companies. This culminated with the nationalization of 42 private railways into a national company named Rede Ferroviária Federal SA - RFFSA, in 1957, with the objective to recover and improve freight transport to support activities associated to some industrial process, basically mining and related activities and, later, agricultural production for exportation (grains). During eighties, however, economical crisis and the consequent lack of public investments challenged the operational capacity of RFFSA, resulting in its inability to meet demand for rail freight services and the need of heavy public subsidies. This culminated with the privatization of freight rail system into vertical companies, under a regional format corridors. Concessions were awarded between 1996 and 1998, on a price cap model, under a contractual regulatory approach, with production-safety targets. Performance improved greatly in the first years of concession, with great investments in rehabilitation of tracks, rolling stock and facilities. On a regulatory perspective, however, the network arrangement did not lend to a competitive design, since lines were disposed as isolated corridors, with no economical links between them and no regulatory enforcement to stimulate interoperability. In 2002, Agência Nacional de Transportes Terrestres - ANTT, a regulatory agency, was created, with a mission to monitor the companies' compliance with contracts and stimulate the improvement of rail sector. In its initial activities, ANTT has developed a basic regulatory framework, aimed at the fulfillment of contractual obligations. However, to improve competition and increase rail market share in Brazilian transport matrix, much has to be done, but honoring awarded contracts. Under this context, in 2011, ANTT developed a regulatory package, focused on stimulating competition, establishing shippers and companies' rights and regulating investments from concessionaires and shippers. Moreover, ANTT is working on contractual tariff revision, which aims the alignment of rail tariffs to the present cost structure of rail sector, in order to transfer to users part of rail sector's some productivity earnings. So, this work is supposed to present a historical view of the evolution of Brazilian freight rail sector, with a critical view of virtues and weakness of concessions, and the efforts of the regulatory agency to improve the sector, while honoring contracts awarded.
Barbosa, Fabio CoelhoMafra dos Reis, JeanMendes de Souza, Alexandre PortoRodrigues, Antonio Sergio
Superbus: A Novel Concept for Safe, Fast and Sustainable Mobility2009-01-05974/20/2009
Sustainable mobility in all its aspects is the philosophy of the Superbus (Fig 1), which is a new concept for public transport that consists of a new vehicle, new infrastructure and new logistics. The Superbusproject is a project started by the chair AeroSpace for Sustainable Engineering and Technology (ASSET) of the Delft University of Technology (Tu Delft) in the Netherlands. The project is funded by the Dutch Ministry of Transport and Water Management and other sponsors with the aim to prove the feasibility of the concept. Sustainable mobility does not only relate to the environmental impact (global warming, CO2 and NOx emissions, etc), but also to the use of infrastructure and the impact of infrastructure on the environment, the safety of passengers and pedestrians, and the effective utilization of he system through its logistics. With the aim to account for all such aspects, the Superbus is non-polluting as it uses four electric motors power by a battery pack; it is lightweight and uses very low power per passenger; uses a number of recyclable materials. Also, its dedicated infrastructure, called supertrack, is cheap, lightweight and relatively easy to be relocated. Next to that, the safety of passengers (internal safety) and the safety of all other traffic including pedestrians (external safety) has played an important role in the development of this new concept, which is massively instrumented for obstacle detection, navigation, control, monitoring and it is provided by a number of passive and active systems for passengers protection. Finally, due to the ever growing transport demand and the increasing request for flexible driven logistics, an advanced information and communication technology has been defined. This latter aspect not also ensures efficiency of the transportation but also eliminates the utilization of a running timetable. In this way there will not be vehicles traveling with few or no passengers. In this paper the evaluation of the various sustainable mobility aspects and consequent impact on the definition of the Superbus transportation system will be described. Then, the resulting design will be discussed.
Terzi, AntoniaMelkert, JorisOckels, Wubbo
Guideway Bus in Practical Use - Seeking for a Pleasant Car Society9215628/1/1992
Japan is the largest automobile producing nation in the world, and its automobile holding has been ranked at the second place, next to the United States (U.S.). The automotive vehicle population has dramatically increased, and it has created overcrowded-situations in urban areas. An increased number of highways has somewhat improved the traffic conditions. However, a deterioration of transportation efficiency has caused poor fuel economy and air quality and it has caused serious concern for the human life in Japanese cities from the perspectives of energy conservation and environmental safety. The Guideway Bus System has been developed as an alternative transportation system to solve the Japanese urban traffic problem. The system reduces the number of cars in the city and retains the convenience of bus transportation systems currently being used in most cities in Japan. The guideway bus system uses a hybrid powerplant consisting of a diesel engine and an electric motor. The system is suitable for small city transportation because of its low construction cost and its high potential for maintaining a cleaner environment by using clean electric power generating plants developed in Japan. This paper describes the present status of the development of the new transportation system which includes the Guideway Bus System and the clean electric power generating plants in Japan. The system has also been compared with those developed by other nations.
Ariga, Hajime
Items per page:
1 – 34 of 34