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Miyauchi T.,Frictional Materials Laboratory | Tsujimura T.,Research and Development Promotion Division | Ishiduka H.,Vehicle Structure Technology Division
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2014

The use of high-strength flame-resistant magnesium alloy appears to be a promising route to reduce the weight of car body shells. Since research and development of flame-resistant magnesium alloy has just started, basic data and processing technologies still need to be investigated. This paper presents the results of investigations on its test processing, evaluation of its mechanical properties and workability. The trial manufacturing of hollow extrudedmaterials and welding processes using this alloy are also briefly described.

Koyama T.,Current Collection Laboratory | Aboshi M.,Research and Development Promotion Division
Quarterly Report of RTRI (Railway Technical Research Institute) | Year: 2013

An increase in undulating wear on overhead conductor rails leads to more frequent arcing through contact loss between the line and the pantograph. Arcs are one of the major sources of extreme conductor rail and contact strip wear. The formation mechanisms of undulating wear however, have not yet been clarified. The authors therefore investigated the sliding surfaces of overhead conductor rails and the dynamic characteristics of pantographs used on commercial lines. Results indicate that the dynamic characteristics of the pantograph and the distance between pantograph heads play a significant role in the appearance of undulating wear. Periodic unevenness is formed by mechanical wear due to the dynamic characteristics of a pantograph; in particular, anti-resonance phenomenon of the pantograph affects this process significantly. Once the undulating wear amplitude grows to the extent that the pantograph cannot keep contact with the conductor rail, arcs due to contact loss frequently occur along the undulating conductor rail causing extreme undulating wear. The wavelength of this extreme undulating wear is related to the interval of the pantograph heads.

Aeaki K.,Meteorological Disaster Prevention Laboratory | Fukuhara T.,Meteorological Disaster Prevention Laboratory | Shimamura T.,Research and Development Promotion Division | Imai T.,Meteorological Disaster Prevention Laboratory
Quarterly Report of RTRI (Railway Technical Research Institute) (Japan) | Year: 2011

The safety of railway line sections against strong winds can be improved by setting up anemometers in locations where wind speeds frequently exceed the critical wind speed of overturning. In order to ensure optimum location of the anemometers, wind speed values need to be estimated over an N-year return period along railway lines. This paper introduces a method to estimate over a given return period the values of the maximum instantaneous wind-velocity along railway lines at interval of 100m, by using two kinds of numerical simulation techniques (the meteorological model and the Computational Fluid Dynamics model) and a topographical factor analysis.

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