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Yasutaka MAKI, Takayuki SHIMOMURA, Kimiaki SASAKI
2009 Volume 50 Issue 4 Pages
193-198
Published: 2009
Released on J-STAGE: December 02, 2009
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We have developed a hardware-in-the-loop simulation (HILS) system as a virtual running-test environment to replace actual test runs. It is essential for the vehicle model in the HILS system to run under real-time conditions and for actual vehicle motion to be simulated accurately. In this paper, we introduce the HILS model and report on the results of amplitude-frequency response tests executed on a rolling stock motion stand to improve the model's performance by modifying its parameters.
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Yasutomo ODA, Tsuyoshi YAGI, Tomohiro OKINO, Hiromichi ISHIDUKA
2009 Volume 50 Issue 4 Pages
199-204
Published: 2009
Released on J-STAGE: December 02, 2009
RESEARCH REPORT / TECHNICAL REPORT
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The fatigue strength of weld surfaces on truck frames has been estimated according to the fatigue limit diagram in JIS E 4207 - General Rules for Design of Truck Frames for Railway Rolling Stock. However, it is not possible to predict actual fatigue life using this diagram. This study demonstrates the possibility of fatigue life estimation of welds on truck frames based on a modified Miner's rule. In order to estimate fatigue life, three factors are needed: the S-N diagram prepared based on the allowable stress in JIS E 4207 or the JSSC fatigue design curve, the relationship between crack occurrence and running distance, and the frequency distribution of stress caused by service loads.
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Ichiro HAGA, Koichi MURAKAMI, Hideo NAKAMURA, Shinichi MAEHASHI
2009 Volume 50 Issue 4 Pages
205-209
Published: 2009
Released on J-STAGE: December 02, 2009
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Understanding actual exhaust emissions is important in executing appropriate measures to reduce them. To this end, we developed an exhaust emission measurement technique that can be executed relatively easily using engine bench test boards at JR rolling stock maintenance depots and in diesel railcars under running conditions. We also clarified the current status of exhaust emissions according to the results of measurement.
Additionally, we investigated a number of the operation modes in commercial trains, and proposed the test cycle concept which was applied to evaluation of measurements based on the analysis results.
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Tomoyasu SUGIYAMA, Osamu NUNOKAWA, Naoyuki OTA
2009 Volume 50 Issue 4 Pages
210-215
Published: 2009
Released on J-STAGE: December 02, 2009
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Railway operators invest in measures to prevent rainfall-related slope failure to secure the safety of train operation. Accordingly, it is essential to evaluate the risk of slope failure by considering the probability and potential cost of such events in order to execute investment effectively. We developed a method of calculating the probability of slope failure caused by intense rainfall to evaluate the risk of slope disaster by applying a risk assessment method. This paper describes the method developed and presents some calculation examples.
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Osamu NUNOKAWA, Tomoyasu SUGIYAMA, Naoyuki OTA
2009 Volume 50 Issue 4 Pages
216-221
Published: 2009
Released on J-STAGE: December 02, 2009
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Slope failure resulting from heavy rainfall on railway lines is a common occurrence, making it essential to minimize the phenomenon in the interests of maintaining safe, punctual train operation. It is also necessary to evaluate the disaster risk of individual slopes by considering the probability and potential cost of rainfall-related slope failure. We developed a method to evaluate the potential for slope collapse using a risk assessment technique. This paper describes the method of priority determination for investment to prevent slope failure caused by intense rainfall through application of the technique developed.
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Toshiaki IMAI, Keiji ARAKI, Takaaki FUKUHARA
2009 Volume 50 Issue 4 Pages
222-226
Published: 2009
Released on J-STAGE: December 02, 2009
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The number of train accidents caused by strong winds has followed a downward trend since the commercial opening of Japanese railways in 1872. Specifically, the number of accidents per train kilometer decreased remarkably to 1/100
th of its original level over a period of 100 years. This reduction is considered to result from the regulation of train operation. The probability of trains encountering winds of a critical speed can be reduced through train operation suspension for a certain number of minutes in particular sections. This paper introduces a method to calculate the probability of trains encountering winds of a critical speed in cases where they follow operating regulations strictly.
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Mitsuru IKEDA, Takeshi MITSUMOJI
2009 Volume 50 Issue 4 Pages
227-232
Published: 2009
Released on J-STAGE: December 02, 2009
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In reducing aerodynamic noise generated by pantographs, it has been found necessary to smooth not only the panhead shape but also that of its support. This is because aerodynamic interference between the panhead and the articulated frame causes distinct aerodynamic noise. However, the details of the mechanism behind such interference have not yet been clarified completely. This paper investigates vortex structures around the panhead and the articulated frame using the CFD technique to show the interference mechanism.
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Kiyoshi ASANUMA, Masamichi SOGABE, Tsutomu WATANABE, Junya OKAYAMA, Ha ...
2009 Volume 50 Issue 4 Pages
233-240
Published: 2009
Released on J-STAGE: December 02, 2009
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The authors proposed a ballasted ladder track equipped with a vehicle guide device to minimize damage in the event of vehicle derailment by a large-scale earthquake. The guide device is joined by a hinge to the outer-gauge side of the longitudinal beams on the track. In this study, the authors verified the load-bearing performance of the vehicle guide device through drop-weight experiments and evaluated its performance and buckling safety by numerical analysis. In addition, ballasted ladder track equipped with the vehicle guide device was laid experimentally on a loop line within the premises of the Railway Technical Research Institute, and its tamping performance was verified.
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Hisayo DOI, Takefumi MIYAMOTO, Yukio NISHIYAMA, Shintaro OHE, Hideya K ...
2009 Volume 50 Issue 4 Pages
241-247
Published: 2009
Released on J-STAGE: December 02, 2009
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A new experimental device has been developed to investigate creep forces between wheels and rails. The device — called the Creep Tester — is applicable to existing rails, and its wheel is capable of rolling on rails while using a specific mechanism to alter any longitudinal creepage generated. The Creep Tester is also equipped with a mechanism for setting wheel yaw angles to induce lateral creepage. Along with a number of other features (including a short measuring time and the ability to set normal forces), the device is advantageous in ascertaining the parameters that affect creep force characteristics.
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