The authors developed an imaging system and a diagnosis algorithm for automating visual inspection of underbody equipment of railway vehicles. The developed system consists of a line scan camera, line lights, a laser Doppler velocimeter and a computer, to scan passing vehicles from the ground. Test results using real vehicles indicate that the system can obtain detailed continuous images of the side of vehicles. The proposed algorithm using template matching and subtraction is designed to be robust against disturbances. The algorithm was tested on images captured under simulated variations in weather and the dirt of underbody equipment. As a result, the algorithm diagnosed, for example, whether the valve was fully open normally with an accuracy of ROC-AUC 0.990.

Helical gears are commonly used in the gear units of railway vehicles in Japan, and these gear units use tapered roller bearings. In order to prevent seizure of bearings, this study examined the use of cylindrical roller bearings with ribs that allow a certain degree of axial displacement of inner rings and outer rings. Their performance was compared with conventional tapered roller bearings through various rotating tests. The results of rotation tests using an actual gear unit showed that the temperature rise immediately after the start of rotation and torque of the pinion shaft is lower in the case of cylindrical roller bearings with ribs than with tapered roller bearings.

In order to further improve the flame retardancy of seat materials in railway vehicles, the authors investigated the use of new flame-retardants. During the selection phase of flame retardants, their attention was focused on intumescent flame-retardants. Intumescent flame-retardant expands and produces char foam during the burning process, and the produced char foam plays a role as a protective shield against rapid flame spread. Various test pieces using the flame-retardants were prepared to confirm their characteristics. The results of cone calorimeter fire tests found that insertion of a resin containing intumescent flame-retardants into the existing seat cushions can improve flame retardancy.

The critical wind speed for overturning is often evaluated using the "RTRI detailed equation." In the equation, the lateral carbody vibration inertia force is considered to be the exerted force affecting overturning, and the lateral vibration acceleration is assumed from previous running test results. This paper shows that the critical wind speed for overturning can be accurately calculated using simulation results of the lateral vibration acceleration occurring at the center of gravity of a car body under strong crosswinds. In addition, a new method is proposed to estimate the lateral vibration acceleration using track alignment irregularity data.

The purpose of this study is to propose a method for evaluating passenger thermal comfort in nonsteady state thermal environments with airflow by cross-flow fans in commuter trains in summer. The proposed method is composed of a human thermoregulation model applicable to non-steady state thermal environments and a statistical model derived from the results of experiments conducted in commuter trains in summer. To evaluate thermal comfort considering the influence of a cyclic wind from cross-flow fans, the proposed method converts the cyclic wind to a constant wind speed equal to the total amount of heat loss from the whole-body calculated by human thermoregulation model. We applied the proposed method to our previous research and confirmed that the observed data and predictions agree well.

Passing Shinkansen trains create track surface flows. Screens are installed on track surfaces to prevent ballast projection due to this flow. However, considering future extensions to high-speed lines and faster Shinkansen running speeds commensurate countermeasures must be developed. Field tests are an effective way to develop such measures, however, conducting research and development using field tests is difficult owing to the risk of ballast projection. This paper therefore describes the development of a wind tunnel test method for flying ballast and ballast screens, and wind tunnel tests to evaluate the possibility of ballast projection and ballast screen lifting.

The setting of the control index for buckling of continuous welded rails in Japan is based on the lowest rail temperature increase at which buckling can theoretically occur. However, there is a considerable difference between the index temperature and the buckling temperature at which actual rail buckling occurs. Therefore, the current buckling control index safety margin may be excessive. In order to improve the accuracy of this control index, it is necessary to estimate the buckling temperature affected by lateral track irregularities. This study proposes a method for easily estimating the buckling temperature of continuous welded rails considering lateral track irregularities measured by a track inspection car.

This paper presents the results of a study to investigate a method for estimating the stiffness of concrete girders when calculating the dynamic factor and deflection. Based on a fatigue test of concrete members, we proposed an estimation formula which takes into account the reduction in bending stiffness due to crack propagation under cyclic loading. In addition, we quantified the stiffness contribution of each type of non-structural member by means of finite element analysis for various girder structures. Finally, we propose a simple method for estimating the equivalent bending stiffness of girders considering reduction in stiffness due to bending cracks after repetitive loading and the stiffness contribution of non-structural members.

For early and automatic detection of crossing rod breakage caused by vehicles forcibly entering in level crossing, we developed a method for detecting crossing rod breakage using surveillance camera images. The proposed method determines the presence or absence of stripes peculiar to level crossing by extracting the color components from images and identifying the spatial frequency of the waveforms converted from the extracted color components. This paper describes the details of the proposed method and the results of performance evaluation tests.

There is a strong need for prolonging the lifetime of electronic signalling equipment to reduce replacement costs. On the other hand, availability of equipment has become an issue due to the recent shortage of semiconductors. Since the actual lifetime of electronic signalling equipment depends on the lifetime of electronic components and solder joints with substrates, it is possible to prolong this lifetime by selecting suitable electronic components and improving the environment of use. In this paper, a method for quantitatively evaluating the effect of measures for prolonging lifetime was investigated utilizing a method developed to evaluate the lifetime of electronic signalling equipment.

Thermal effects on trackside signalling devices, such as high air temperature, intense sunlight, and Joule heat generated by return currents, can be tested independently. However, it is difficult to evaluate the effects of multiple sources of heat. And yet, trackside signalling devices have occasionally failed due to heat, for example, deformation of the device structure because of heat. To reduce such failures, we developed a method for evaluating thermal effects on a resin-molded impedance bond using a computer simulation of heat-stress analysis. In this paper we also propose a method for evaluating thermal effects on impedance bonds through a combination of analytical and experimental methods.

As a baseline study on the provision of information to enable prompt evacuation from a train, different types of evacuation were grouped into three categories: immediate evacuation with passengers only, evacuation by remote instruction and evacuation by Staff Guidance. A web-based survey showed that there is a certain degree of role awareness in fellow passengers helping each other during escape, and that cooperative behavior can be expected. It also showed that those who understood instructions more clearly tended to act more immediately. Thus, it is considered important to inform passengers about their expected role, the flow of action to be taken, and the overall evacuation process.