Quarterly Report of RTRI

PAPERS

Safety Assessment for Flange Climb Derailment of Trains Running at Low Speeds on Sharp Curves

Hiroaki ISHIDA, Takefumi MIYAMOTO, Eiichi MAEBASHI, Hisayo DOI, Kouhei ...

2006 Volume 47 Issue 2 Pages 65-71
Published: 2006
Released on J-STAGE: August 24, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.65

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Flange climb derailment of railway vehicles occurs during low-speed running on sharply curved and twisted tracks. We studied the mechanism behind flange climbing to clarify and quantify the factors that cause derailment. In this study, passenger vehicle running tests were carried out on an RTRI test line subsidized by the Ministry of Land, Infrastructure and Transport. Derailment actually occurred during the tests, which measured wheel/rail contact forces, the forces exerted on the wheel sets and the dynamic behavior of the vehicle. Bench tests were also performed using roller rigs to investigate the characteristics of creep force. Based on the test results, this paper proposes a method to assess levels of safety against vehicle derailment on curved tracks.

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Study on Optimization of Panhead Shape Possessing Low Noise and Stable Aerodynamic Characteristics

Mitsuru IKEDA, Masahiro SUZUKI, Kazushige YOSHIDA

2006 Volume 47 Issue 2 Pages 72-77
Published: 2006
Released on J-STAGE: August 24, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.72

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Two main concerns with pantographs used on high speed trains have been their aerodynamic stability and aeroacoustic noise reduction. These properties depend on the shape of the pantograph, but these is often a trade-off between them and pantograph design is therefore a very delicate process. As many wind tunnel tests are required before an adequate shape is found, the process is time-consuming and expensive. To improve the efficiency of a new-type pantograph development, a new design process including computational fluid dynamics (CFD) and optimization techniques was proposed to provide a suitable shape possessing the appropriate aerodynamic and aeroacoustic properties. The results of some wind tunnel tests on some panhead models designed using this method show that it can be useful for panhead design.

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Development of Monitoring System for Electric Switch Machine

Yoshinobu IGARASHI, Syunsuke SIOMI

2006 Volume 47 Issue 2 Pages 78-82
Published: 2006
Released on J-STAGE: August 24, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.78

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There is a need to improve the maintenance of electric switch machine in particular the locking mechanism, which needs precise adjustment to within 0.1 mm. The position of the lock rod deviates slightly with each switching motion, making it difficult to monitor the status of the lock adjustment. A new monitoring system, developed for electric switch machine, is capable of adjusting the lock more accurately. Furthermore, the system enables providing information on the dynamic characteristics of the switch upon train passage.

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Application of Ad-hoc Network Technology to Railway Systems

Kiyotaka SEKI, Kunihiro KAWASAKI, Kazuki NAKAMURA

2006 Volume 47 Issue 2 Pages 83-88
Published: 2006
Released on J-STAGE: August 24, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.83

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As tentative mobile networks can be easily constructed using ad-hoc network technology, hopes are high for its application across a range of fields. In this paper, we show the results of basic studies for its application in railway operational systems. First, we propose two application systems that can be constructed using ad-hoc network technology and clarify their transmission characteristics through simulation. We then report the measured values of radio propagation characteristics at varying frequencies suitable for use in ad-hoc networks constructed at stations and waysides. Finally, we introduce a radio propagation characteristics estimation program extended to include calculation of the propagation characteristics between two mobile nodes.

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Performance Evaluation of Radio-based Train Control System

Hiroshi FUKUOKA, Kohji IWATA

2006 Volume 47 Issue 2 Pages 89-94
Published: 2006
Released on J-STAGE: August 24, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.89

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In general, the railways have kept their systems highly safe and reliable through the ongoing efforts over a period of many years. This has been achieved primarily by continuous improvements, which mean that there is a dearth of experience in the introduction of innovative new systems.
Therefore it is said that comparing a new system that features a completely new architecture with a conventional one may be difficult. With this in mind, we developed a method of evaluating the effect of a new system architecture and took a radio-based train control system as an example. Then we described the result of a case study that evaluated the realtime, safety and reliability properties of the new train control system.

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Evaluation of Natural Slope Stability using Digital Elevation Models and Satellite Imagery

Takehiro OHTA, Atsushi HASEGAWA, Hideaki ENOMOTO

2006 Volume 47 Issue 2 Pages 95-99
Published: 2006
Released on J-STAGE: August 24, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.95

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Natural disasters are not only by geomorphologic, geologic and hydrogeologic conditions but also by vegetation and artificial civil workings. These conditions can be evaluated qualitatively based on aerial photography analyses and field surveys. The quantitative evaluation of natural slope stability is carried out using digital elevation models (DEMs) and high-resolution satellite imagery. In the homogeneous geologic condition area, DEMs can detect the geomorphologic features involved in natural disasters, and satellite imagery can evaluate vegetation. Therefore, we consider that natural slope stability is estimable by a combination of geomorphologic attributes calculated from DEMs and vegetation indices obtained from satellite imagery.

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Development of General Evaluation System for Seismographs and its Installation in Early Earthquake Detection Systems

Shinji SATO, Kimitoshi ASHIYA, Hiromitsu NAKAMURA

2006 Volume 47 Issue 2 Pages 100-104
Published: 2006
Released on J-STAGE: August 24, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.100

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Compared with their predecessor, the new systems (DataStation, DataCraft) that we have developed offer various advantages such as an increase in the number of types of seismographic equipment applications, the provision of an early earthquake detection process function and the capability to process a large quantity of data collectively. Early earthquake alarm seismographs will be installed along the meter gauge lines in the near future. Before the existing seismographs are replaced with these early earthquake alarm seismographs, we should confirm the suitability of the new system based on the analysis of past data.

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Development of Quakeproof Reinforcement Methods for Masonry Walls

Tomoyasu SUGIYAMA, Naoyuki OTA, Osamu NUNOKAWA, Satoshi WATANABE

2006 Volume 47 Issue 2 Pages 105-110
Published: 2006
Released on J-STAGE: August 24, 2006

DOIhttps://doi.org/10.2219/rtriqr.47.105

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Although progress has been made with quakeproof reinforcement works for various structures since the Hyogoken-Nanbu-Earthquake (1995 Kobe Earthquake), this has not yet included masonry wall reinforcement. We therefore carried out investigations into the current condition of masonry walls constructed along railway lines, and performed some experiments with a scale model of a masonry wall using a shaking table. This paper: (1)provides an outline of new quakeproof reinforcement methods for masonry walls; (2)reports on the shaking table tests carried out to verify the effectiveness of the methods; and (3)gives the study results obtained using execution methods applicable to substantial reinforcement works.

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