In order to analyze the behavior of railway vehicles subjected to crosswinds in more detail, we constructed a simulation program applying a full-vehicle model developed from a half-vehicle model. Using the full-vehicle simulation program, investigations were made into the influence of factors not considered in the half-vehicle model on overturning or wheel unloading ratio. Results revealed that the wheel unloading ratio reaches the maximum value when the yawing moment is zero. It also became apparent that when considering the relationship between the wind speed and the wheel unloading ratio or overturning, the relationship could be appropriately evaluated by using the wheel unloading ratio averaged through the vehicle as an indicator, regardless of the static wheel load imbalance of each axle.

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This paper presents a technique for damper fault detection based on the phase difference between the bounce and pitch motions of bogie frames or a car body obtained with inertial sensors. This method avoids the need for mounting sensors in oil dampers. The result of vibration excitation tests with one vehicle on a testing plant demonstrated that the faults in a primary vertical damper were detectable by evaluating the phase difference between the bounce and pitch motions of the bogie frames. The results of running tests on a meter-gauge line demonstrated that secondary vertical damper faults were also detectable based on the phase difference between the bounce and pitch motions of the car body.

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Recent years have seen some railway vehicles equipped with secondary batteries on board to improve their energy saving performance. Such vehicles need accurate and stable SOC (state of charge) estimation, which is important for managing battery energy. This paper reports on a SOC estimation method for on board lithium ion batteries developed for the contact-wire and battery hybrid electric railway vehicle. This method enables stable SOC estimation and automatic tuning of parameters, such as battery capacity and battery inner resistance. These characteristics of the estimation method were evaluated by way of running tests on the JR-Shikoku Yosan railway line.

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Recently earthquake ground motions with high frequency components have been observed on a regular basis. It is well known that the "effective input motion" is reduced in the high frequency range due to the effect of Kinematic interaction of the soil-pile system. Dynamic soil-pile interaction analyses, therefore, were conducted by varying the conditions of both the ground and piles, and the influence of input loss from the pile foundation was investigated. The result revealed that the input loss was negligibly small in case of ground motion whose amplitude was predominantly in the 1-2 Hz range, such as the Hyogoken Nanbu earthquake. On the other hand, the input loss was quite large in the case of high frequency seismic motion such as that observed in the Tohoku earthquake. A simplified expression of input loss, which could be used in practice for seismic design and is based on the Winkler-type spring model, was proposed.

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Visual inspection methods are currently used on existing retaining structures. Consequently it is difficult to evaluate a structural health of the retaining walls quantitatively. In this study, a series of model tests on retaining walls were carried out to develop an inspection method for quantitatively evaluating existing railway retaining walls. It has been found from the series of model tests that vibration tests are an effective means to determine the vibration characteristics of retaining walls, which reflect their structural health. Test results indicated that small scale vibration tests could be applied to evaluation the structural health of existing retaining structures.

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In the design of RC members, reinforcement arrangement methods are determined according to structural details of reinforcement, since the latter are preconditions for applying a specific design method. However when reinforcement arrangement methods are applied to members in small sections, it is difficult to validate the method adequately. This difficulty arises because the methods have been proposed for the members on comparatively large sections. Consequently, in this study loading experiments and analyses were performed on specimens for a number of different reinforcement arrangements. For example, various reinforcement diameters and spacing were investigated. The influence of structural details in the reinforcement arrangement method on deformation performance of RC members was clarified. Finally a reinforcement method was proposed based on mechanical theory considering the buckling of longitudinal bars.

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The authors design and develop a prototype DC superconducting cable for railways. For the preliminary evaluation 2 m Bi-2223 DC cable is used. The maximum current flowing in the cable cooled by liquid nitrogen was 1720 A in the inner sheet wire and 2430 A in the outer sheet. The experimental results and simulations led to the conclusion important for practical applications that the leakage of magnetic field was negligible. This result is of crucial importance, in particular for use in railway systems.

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This paper describes some experimental investigations of on-the-spot X-ray analysis of interfacial substances between the wheel and the rail such as iron rust and lubricants, which have an influence on the adhesion coefficient between wheel and rail. A portable X-ray analyzer called "XRDF" was fitted with a fixture for setting the XRDF head above the rail by making it override the rail. By conducting in situ XRDF analysis of rail surface substances, insights were obtained into the tendencies regarding the decrease of iron rust and the spreading characteristics of lubricants during the passage of vehicles.

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In order to install extra-high soundproof plates on existing soundproof walls while avoiding drastic viaduct reinforcement work, a new type of soundproof plate system was developed called SSRW (soundproofing system equipped with a mechanism of reducing wind load). These plates not only provide effective soundproofing they can also deflect wind load exerted on them maintaining the safety of the viaduct in strong wind conditions. Plate movement is controlled by magnetic attractive force, and the magnetic attractive force around the soundproof plates was calculated by magnetic field analysis. Wind tunnel tests were performed using full-scale prototype of the SSRW and measurements were made of its soundproofing performance to verify the reported mechanism and properties.

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The following correction should be made to the original paper: May, 2013 Vol.54, No.2, Page 80, u(xi, yi+1) (Roman type) should be changed to u(xi, yi+1) (Italic type).

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