A new wheel slide detection and control system is developed for the railway vehicles. Recently, the number of new model vehicles where the anti-lock braking system (ABS) was installed is increasing to prevent the wheel slide that causes increase in the braking distance and damage to the wheel. The ratio of the number of vehicles in which ABS is installed is high in new vehicles, and low in old model vehicles. A new system is proposed to detect wheel slide by two methods, using with the detection of the wheel rotation speed and the difference of the rotation speeds of two wheels. When the wheel slide is detected, ceramic particles are ejected between the front wheels of the foremost bogie and the rails. Ceramic particles increase the adhesion force between the wheel and the rail, and the wheels recover from the sliding condition. The jetting of ceramic particles is monitored by the newly developed particle flow-rate sensor. The effectiveness of the proposed system is verified by the experimental runs using the limited express and the suburban trains. The results show that the wheel slide can be detected at every case and is suppressed within a few seconds. Compared with ABS, the proposed system is simple and less expensive. Thus, the proposed system has large possibility to be installed to wide range of vehicles including the old model vehicles which do not have ABS systems.

抄録全体を表示

The critical wind speed of overturning obtained by the RTRI detailed equation, which is used in the static analysis of railway vehicle overturning under cross wind, tends to be lower than that intuitively estimated because it assumes the superposition of the worst conditions. In order to improve the accuracy of the evaluation, the previous research focused on the aerodynamic coefficients that have the greatest influence on the calculation results, but few studies on the lateral vibrational inertia force have been conducted. Therefore, in order to evaluate the critical wind speed of overturning reflecting the actual conditions, we examined an evaluation method based on the measured value of the lateral vibrational acceleration.

抄録全体を表示

To prevent wheel slips and wheel slides of trains, a particle jetting device has been installed as a type of sanding devices. In this device, the adhesion between wheels and rails is increased by jetting ceramic particles between wheels and rails. In the previous paper, a monitoring system of particle flow in the device was proposed, and the performance of the system was verified through the bench test. The assured actuation of the device is indispensable to the safe operation of high speed vehicles. It is very important to verify the performance of the developed system through real operating conditions of trains. From that viewpoint, the results of running tests at several types of trains and several types of operating conditions are analyzed in this manuscript. The vibration of the particle jetting device affects the monitoring performance because the proposed system detects the particle flow by measuring the static electricity of flowing particles in a tube. Thus, the vibration at real operating condition was measured using accelerometer installed in the bogie frame. The results of test runs showed that the proposed monitoring system functions well at every condition and has high possibility to apply real operations.

抄録全体を表示

Vertical vibrations in railway vehicles are not only induced by track irregularity but also affected by the rotation of wheelsets with small mass imbalance. It is known that the excitation force generated by the rotation of wheelsets is transmitted from bogies to car bodies through longitudinal connecting members such as traction devices and yaw dampers. In this research, we first investigated the influence of yaw dampers on the vertical car body vibration induced by the rotation of wheelsets. Roller rigs rotation tests were performed using a full-scale vehicle with/without yaw dampers. In cases where there was no yaw damper, the vertical vibration of the car body was lower than that of cases where yaw dampers were equipped. This result indicates that vibration transmissibility from bogies to car bodies via yaw dampers should be reduced. In order to suppress this vibration transmission, we developed two vibration reduction devices: a new mounting structure for yaw dampers having a moving beam, and displacement-dependent rubber bushes for yaw dampers. The results of roller rigs rotation tests show that the developed devices reduced the car-body vertical vibrations caused by the excitation forces via yaw dampers. Moreover, we conducted running tests on a commercial track, and the results show that the vertical car body vibrations were reduced by applying displacement-dependent rubber bushes for yaw dampers.

抄録全体を表示

Various parts and equipment are attached to the bogie of the railway vehicle. These parts are subjected large vibration during running. The accident rarely happens that the parts are fall by this vibration. Therefore, the vibration prediction technique of the bogie is needed. The authors have proposed a method of predicting the vibration at the evaluation points in the bogie from the impact test carried out with the vehicle stationary. It was confirmed that the proposed method could predict the vibration during the running on the commercial line up to 100km/h. In the previous research, only one vehicle was examined. In this paper, the results of applying to the other two vehicles were shown. As the result, the proposed method could be applied to two vehicles. However, it was shown that the best condition of the impact test was different according to the type of vehicle or the evaluation point. Therefore, the running test results in the depot were used as a new excitation method. The accuracies of the prediction were improved by using the results of running test in the depot. However, it was needed that the multiple coherences between the vertical acceleration of the axle boxes and evaluation point were sufficiently large.

抄録全体を表示

In Japan, the maximum speed of meter-gauged railway lines (conventional lines) is 160km/h. In recent years, the overhead contact line with a feeder messenger wire, which has the features of labor-saving maintenance and construction cost reduction, has attracted attention. Because further high-speed performance is required, even for meter-gauged railway lines, the development of the overhead contact line with a feeder messenger wire that has excellent high-speed performance is desired. Therefore, compound catenary equipment with a feeder messenger wire has been developed for meter-gauged railway lines. This overhead contact line enables a train to operate at a speed of 160km/h and maintain the features of labor-saving maintenance and construction cost reduction. We performed theoretical analyses and a dynamic-characteristic evaluation to confirm the validity of the overhead contact line. Moreover, we conducted a test run to verify the current collection performance of the overhead contact line.

抄録全体を表示

In DC electric railways, power is supplied to trains from DC substations. The voltage gets declined at a pantograph on the way due to the voltage drop caused by impedance, in particular the resistance of feeding wires. In case the load of rolling stock gets heavy, the significant voltage drop may hinder the train from continuous operations. Two methods have been conventionally used to deter the voltage drop. One ways is to decrease resistance of the circuit by the application of feeder with bigger diameter. Another is to compensate the voltage drop by the installation of the new substation between two existing substations. These two methods are effective; however, there are problems of term and cost for installation. Based on these issues we have recently developed the new method which we call "substation support equipment". In this paper we report the basic concept and overview for the substation support equipment together with results of performance test on site and artificial fault test.

抄録全体を表示

After the Mid Niigata Prefecture Earthquake in 2004, research and development of earthquake countermeasures has started for Shinkansen trains. Some technologies for improving running safety of the Shinkansen trains during an earthquake have been applied to commercial lines and vehicles. Regarding conventional lines, earthquake countermeasures are also taken a growing interest, especially in metropolitan areas. At first, conventional guard angles which are usually placed on sharp curves are considered as the earthquake countermeasures due to cost restrictions. For the trains which have yaw dampers, this paper proposes to change the layout of the yaw dampers to longitudinally symmetrical position in bogie as another countermeasure against an earthquake. This paper also numerically clarifies that the proposed layout of yaw dampers improves running safety against sinusoidal oscillation. In addition, the actual bogie oscillation test is performed to valid the numerical results. From probabilistic perspective the authors show that the conventional guard angle and the proposed layout of yaw dampers have almost the same effects on improving running safety for seismic vibration of track.

抄録全体を表示

It is one of the important issues to investigate the vibration behavior of railway bogies, since the vibration of the bogies may result in loosening bolts which fix the parts to the bogie frames or/and fatigue fracture of the parts themselves. A technique for predicting the vibration of bogie parts is proposed by which the acceleration power spectral densities (PSDs) at evaluated points are predicted with the use of frequency response functions (FRFs) between the axle boxes and the evaluated points, together with the use of measured accelerations of axle boxes. Stationary excitation tests are conducted to identify the FRFs, and the axle boxes or rails were hit with impulse hammers to excite the bogies. Alternatively, the new approach without the stationary tests is also proposed in this study. In this case, the FRFs are identified with the accelerations acquired in the preliminary running tests in car depots. The proposed technique is applied to the vibration prediction of the bogies for several types of railway vehicles including electric cars and a diesel car, and the differences or ratio between the predicted and actually measured PSDs are evaluated. It is confirmed that the preliminary running tests are preferable to stationary excitation tests for improving the prediction accuracy. It is also verified that the prediction error can be reduced in the case where not only the vertical but the lateral and longitudinal accelerations of axle boxes are considered as the excitation inputs under the conditions that the principal component regression is applied to identify the FRFs.

抄録全体を表示

After the Mid Niigata Prefecture Earthquake in 2004, research and development of earthquake countermeasures has started for Shinkansen trains. Some technologies for improving running safety of the Shinkansen trains during an earthquake have been applied to commercial lines and vehicles. Regarding conventional lines, earthquake countermeasures are also taken a growing interest, especially in metropolitan areas. At first, conventional guard angles which are usually placed on sharp curves are considered as the earthquake countermeasures due to cost restrictions. For the trains which have yaw dampers, this paper proposes to change the layout of the yaw dampers to longitudinally symmetrical position in bogie as another countermeasure against an earthquake. This paper also numerically clarifies that the proposed layout of yaw dampers improves running safety against sinusoidal oscillation. In addition, the actual bogie oscillation test is performed to valid the numerical results. From probabilistic perspective the authors show that the conventional guard angle and the proposed layout of yaw dampers have almost the same effects on improving running safety for seismic vibration of track.

抄録全体を表示