We have developed a new-concept bogie for gauge-changeable trains that is applicable to both standard gauge 1,435-mm line and meter gauge 1,067-mm line. The bogie must therefore feature good running stability at high speeds on standard gauge lines as well as high running performance on the curves of meter gauge line. It adopts a direct-drive motor system to enable the motor to be mounted directly to the wheels, an independent wheel system and a wheel-set steering system. The independent wheel system provides the bogie with good running stability at high speeds with a short wheelbase. We tested the model on our rolling stock test machine, and confirmed that no stability problems occurred at speeds of up to 500 km/h. We also conducted high-speed performance testing at the Transportation Technology Center Inc. in Pueblo, Colorado, USA, and on the Sanyo Shinkansen line in Japan at speeds of over 200 km/h.

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In order to reduce the energy consumption of railway vehicles, we have developed a new kind of energy storage equipment that is connected in series to the DC side of traction inverters. The equipment boosts the input voltage of the traction inverter so that the motor torque increases in the high-speed region and the mechanical brake force decreases. In this paper, we describe the fundamental operation and energy-saving performance of the proposed equipment.

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This paper reports on the dynamic characteristics and a non-linear model of an air spring for vertical motion. The creation of a dynamics model that closely expresses air spring characteristics enables accurate estimation of the dynamic characteristics of vehicles, and contributes to the improvement of ride comfort. Based on the results of characteristics confirmation test on the air spring, a dynamics model of the air spring was examined. It was found that the damping characteristic of the air spring was neither viscous (linear) nor quadratic, but proportional to a velocity exponent of about 1.7.

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In general, the safety for earthquake defined as the performance to prevent from collapsing of structures. However, accurate verification of collapse of structures requires adequate comprehension of seismic behavior in large deformation response, and precise evaluation of limit value of collapse. In this study, we conducted shaking table test using earthquake wave of main quake and after quake and examined the dynamic behavior of RC columns. As a result, it is evident that even if seismic response of structures reaches to the limit value of collapse in the current design standard, structures are not always collapsible, and even if structures prevented from collapsing in a major seismicity, structures may collapse after the quake depending on seismic characteristics. Therefore, we proposed a new verification method using the amplitude of response displacement for the safety performance.

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Many brick piers built in Japan's Meiji or Taisho eras (i.e., between 1868 and 1926) remain in service even today. As these aged structures generally have low seismic stability, an appropriate reinforcement method needs to be adopted. This paper describes new information related to the seismic stability characteristics of old piers and foundations, and outlines a method for quakeproof reinforcement.

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It is well known that the strength of reinforced concrete columns is degraded by cyclic loading, particularly in the post-peak region. In examining the seismic safety of RC structures, it is important to conduct dynamic response analysis that considers strength degradation caused by cyclic loading. In this study, we first developed a nonlinear dynamic hysteresis model that can take into account strength degradation. Secondly, we attempted to evaluate the effects of duration time of earthquake motion in the post-peak region through seismic response analysis using the proposed model. The results clarified that the post-peak behavior of reinforced concrete structures varies depending on the duration time of the ground motion.

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The periodicity of motor disassembly maintenance in railway vehicles is currently determined by the durability of the sealed grease they contain. The lifetime of this grease is the shortest of all the motor's bearing parts and materials, and therefore needs to be made longer. To this end, therefore, the authors discussed the shape of the grease pocket, and concluded that the efficiency of lubrication depends on the shape of the pocket and the relative position between pockets and the bearing, which should be appropriately modified. In this report, the authors first introduce examples of the improved grease pocket shape together with the results of laboratory testing on the base-oil behavior, then show the results of laboratory tests using full-scale grease pocket models with conventional and modified shapes to compare the service lives and determine the effects of improvement.

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We produced a test-manufactured lip-type seal to suppress outbreaks of flaking (of rubber and filler) on lip contact surfaces as one of a number of measures to cope with increased speeds of 350 - 400 km/h in Shinkansen vehicles. The results of bench testing on its high-speed rotation performance showed no leakage of oil with a number of rotations equivalent to a vehicle running distance of 750,000 km, and the condition of the seal after the test was satisfactory. This rotary shaft lip-type seal was thus confirmed as offering a suitable level of performance for use in high-speed Shinkansen vehicles.

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Plain bearings equipped with railway freight cars frequently suffered from surface damage caused by electrical current. This paper describes a newly developed earth device as designed to prevent electrical conduction in such bearings. The developed earth device can be installed on existing freight car axle boxes and readily assembled and removed upon regular inspection. In a durability test for electrical conduction until 21,600 km equivalent journey distance, the electrical resistance of the earth device was 100 - 300 mΩ. It also satisfied the requirements of a durability test for mechanical vibration in accordance with JIS E 4031.

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