Quarterly Report of RTRI
Online ISSN : 1880-1765
Print ISSN : 0033-9008
ISSN-L : 0033-9008
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Volume 55, Issue 3
Displaying 1-9 of 9 articles from this issue
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PAPERS
  • Development of Electro-hydraulic Actuator with Fail-safe Function for Steering System
    Yasuhiro UMEHARA, Shogo KAMOSHITA, Kotaro ISHIGURI, Yusuke YAMANAGA
    2014 Volume 55 Issue 3 Pages 131-137
    Published: August 01, 2014
    Released on J-STAGE: October 03, 2014
    DOIhttps://doi.org/10.2219/rtriqr.55.131
    JOURNAL FREE ACCESS
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    Bogie angle linked steering trucks have an excellent curving performance in circular curve sections. In order to gain even greater curving performance, a power-assisted steering system was developed for reducing wheel lateral forces in transition curve sections by generating the control force in the turning direction of the steering truck. In addition, a steering electro-hydraulic actuator was designed for reducing lateral forces in transition curve sections while preventing wrong direction steering operation which is the biggest problem with active steering systems. Finally, confirmation was obtained through running test on a test line that this steering actuator improved steering performance and maintained the fail-safe function.
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  • Development of a High Efficiency Induction Motor and the Estimation of Energy Conservation Effect
    Minoru KONDO, Minoru MIYABE, Shinichi MANABE
    2014 Volume 55 Issue 3 Pages 138-143
    Published: August 01, 2014
    Released on J-STAGE: October 03, 2014
    DOIhttps://doi.org/10.2219/rtriqr.55.138
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    Induction motors are widely used as traction motors on trains. Because energy loss from traction motors accounts for a large portion of energy consumption in commuter trains, highly efficient traction motors are very effective in saving energy. A high efficiency induction motor was therefore developed. Its efficiency was verified through analysis and tests with a prototype machine. This paper presents the calculation results of running simulations for estimating the energy conservation effect of the high efficiency induction motor. The results indicate that the energy consumption is reduced by 6% to 11%.
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  • Quantitative Evaluation of the Flaw Echo of Railway Axles in Consideration of Contact Pressure with a Wheel
    Kazunari MAKINO, Hiroshi SAKAMOTO
    2014 Volume 55 Issue 3 Pages 144-151
    Published: August 01, 2014
    Released on J-STAGE: October 03, 2014
    DOIhttps://doi.org/10.2219/rtriqr.55.144
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    For railway axles, the wheel seat is periodically inspected by ultrasonic testing. When the ultrasonic axle inspection is performed while the wheels are mounted, the flaw echo height varies depending on the fitting condition. When the inspection is performed on an in-service axle, the echo height also varies under the influence of the bending load acting on the axle due to the car weight. In this study, the variation in echo height due to the contact pressure with a wheel was quantitatively evaluated by simulation of ultrasound propagation. Moreover, the echo-height variation during cyclic rotating bending in a full-sized wheelset was investigated experimentally by studying variation in normal stiffness at the axle-wheel interface.
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  • Risk Evaluation of Debris Flow Using a Digital Terrain Model
    Osamu NUNOKAWA, Naoyuki OTA
    2014 Volume 55 Issue 3 Pages 152-156
    Published: August 01, 2014
    Released on J-STAGE: October 03, 2014
    DOIhttps://doi.org/10.2219/rtriqr.55.152
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    In order to ensure safe train operation, it is necessary to identify, beforehand, areas along railway lines exposed to various kinds of high risk related to slope collapse during rainfall. A method was developed to evaluate the stability of slope surface layers based on predicting changes in groundwater levels by using a simple calculation model in consideration of three-dimensional geomorphologic features. Risk evaluation of debris flows were then studied using this model.
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  • A Simplified Method for Estimating Outflow from the Bottom of Snowpack
    Masaya SHISHIDO, Yasushi KURIHARA, Daisuke TAKAHASHI, Yasushi KAMATA, ...
    2014 Volume 55 Issue 3 Pages 157-163
    Published: August 01, 2014
    Released on J-STAGE: October 03, 2014
    DOIhttps://doi.org/10.2219/rtriqr.55.157
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    To ensure the safety of train operations, it is important to estimate the outflow from the bottom of snowpack which might incur a full-depth avalanche. Therefore, the authors examined a simplified method for estimating the outflow from the bottom of snowpack, which can be applied to railway disaster prevention, on the basis of heat balance observations, snowmelt observations and previous studies. Consequently, the simplified method, which combines a snowmelt (heat balance) model and a percolation model, yields a good estimate of the outflow from the bottom of snowpack at 1 hour intervals using four input data available from the nearest AMeDAS: i.e., air temperature, precipitation, wind speed and duration of sunshine.
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  • Real-time Prediction of Earthquake Ground Motion Using Seismic Records Observed in Deep Boreholes
    Hiroyuki MIYAKOSHI, Seiji TSUNO
    2014 Volume 55 Issue 3 Pages 164-170
    Published: August 01, 2014
    Released on J-STAGE: October 03, 2014
    DOIhttps://doi.org/10.2219/rtriqr.55.164
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    In the case of local earthquakes, a method for predicting earthquake ground motion directly using P-waves observed in deep boreholes, makes it possible to issue earthquake early warnings more simply and reliably compared with the present system. In addition, a method for predicting earthquake ground motion using S-waves observed in deep boreholes and S-wave velocity structures, makes it possible to show the planar distribution of earthquake ground motion, which may narrow down the areas where emergency inspections should be conducted following earthquakes. To develop those two methods, investigations were conducted into the relationship between the peak amplitudes of earthquake motion on the surface and those in deep boreholes using seismic records from KiK-net.
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  • Analysis of Rolling Contact Behavior between Wheel and Rail through Large-scale Parallel Computing
    Hirotaka SAKAI, Masakazu TAKAGAKI, Masae HAYASHI, Akira AIKAWA
    2014 Volume 55 Issue 3 Pages 171-175
    Published: August 01, 2014
    Released on J-STAGE: October 03, 2014
    DOIhttps://doi.org/10.2219/rtriqr.55.171
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    This paper attempts to analyze dynamic wheel/rail rolling contact through application of a three-dimensional finite element method with large-scale parallel computing. This analysis clarifies the dynamic behavior of the contact patch, when a wheel rolls on a rail at a high speed with loading torque. A rail model which allows efficient calculation was developed to accelerate a wheel on a small size rail model. In addition, this method employs dynamic mesh partitioning to maintain meshes in the contact patch in one partition region during the wheel rolling for efficient parallel calculation. Using this method has made it possible to evaluate the dynamic wheel/rail rolling contact behavior.
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  • Analytical Study of Structural Member Vibration Characteristics of Reinforced Concrete Rigid Frame Viaduct
    Tsutomu WATANABE, Masamichi SOGABE, Munemasa TOKUNAGA
    2014 Volume 55 Issue 3 Pages 176-183
    Published: August 01, 2014
    Released on J-STAGE: October 03, 2014
    DOIhttps://doi.org/10.2219/rtriqr.55.176
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    In order to analyze effectively the response of the members of a railway reinforced concrete rigid frame viaduct to the vibration, a new analysis method was developed. It divides the whole railway system into a vehicle / track model, and a track / structure model. These models were used to examine the influence of various vehicle, track and structure parameters on structural member vibration. The dominant factors were quantified for each frequency concerning the response of the center slab at a train speed of 270 km/h.
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  • A Basic Study on Aerodynamic Noise Reduction Techniques for a Pantograph Head Using Plasma Actuators
    Takeshi MITSUMOJI, Yuichi SATO, Mitsuru IKEDA, Takeshi SUEKI, Koji FUK ...
    2014 Volume 55 Issue 3 Pages 184-189
    Published: August 01, 2014
    Released on J-STAGE: October 03, 2014
    DOIhttps://doi.org/10.2219/rtriqr.55.184
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    Reducing aerodynamic noise emitted from a pantograph head is an important environmental factor to be examined in the light of increasing the running speed of Shinkansen trains. This paper discusses control of flow around the pantograph head using plasma actuators. The results of the wind tunnel tests show that plasma actuators can prevent flow separation from the pantograph head surface and weaken Karman vortices. In addition, CFD results indicate that the plasma actuators can reduce aerodynamic noise emitted from the pantograph head.
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