In order to ensure that the railways remain a sustainable transport mode into the future, it is essential to improve the reliability and stability of train operations and railway systems. Functional failures in power supply systems significantly affect train operation: the RTRI has therefore been tackling the issue of improving reliability of power supply systems. This paper describes recent power supply technology research focusing on research geared to contribute to reducing failures and accidents on the railway system.
The purpose of the signalling and transport information division is to contribute to enhanced railway safety, reliability, and convenience through research and development into signalling systems, communication network technology, transportation planning and traffic operations technology, and condition monitoring technology for railway facilities. This paper outlines trends in research and development on improving the safety and availability of signalling systems and telecommunication systems using Information and Communication Technology (ICT) such as image analysis, artificial intelligence, cloud computing, and mobile communications networks.
This paper introduces the latest research and development through numerical analyses and experimental tests conducted by the Railway Dynamics Division on overhead contact lines, railway vehicles, tracks and structures. This includes analyses, tests on the interaction of the overhead lines and pantographs, wheel/rail rolling contact, developments relating to the wheel load reduction control bogie and the low cost ladder sleeper based on wheel load measurements. This paper also introduces the development status of the "Railway Simulator" using advanced HPC (High performance Computing), designed to clarify dynamic phenomenon to optimize the railway system.
This paper describes a new voltage adjustment technique and its design method. In the new design, a voltage compensator, comprising a variable inductor and a controller, is connected with a transformer and a rectifier on either side in series. The authors developed a new configuration of the variable inductor suited for railway application, with a focus on six-phase AC and large current capacity. A fast simulation method for designing the inductor was developed based on the magnetic flux circuit theory and the non-linear simulation technique for ferromagnetic materials.
Electrical connections between the contact wire and the messenger wire are always subject to fatigue damage due to vibration caused by the passage of pantographs. Therefore, it is necessary to clarify the fatigue mechanisms affecting electrical connections to propose measures to mitigate damage. In this paper, the authors focus on the resonance of the electrical connection with catenary system and relative vibration displacement between the contact wire and the messenger wire considering them as major fatigue factors. As a result of OCL-pantograph simulation, the authors clarified the conditions under which fatigue damage of the electrical connection can occur. In addition, the authors proposed a new electrical connection which has a fatigue life exceeding 10 million vibration cycles.
Battery-powered electric trains charge their batteries through collection of a large current from contact wires through their pantographs whilst at a standstill in stations. This current tends to be larger than that collected by normal trains when immobile in a station. Usually, current flowing through a contact wire causes an increase in the temperature of the contact wire. In the case of battery-powered electric trains, pantograph contact strips do not slide along the contact wire in non-electrified sections, allowing an oxide-like film to form on the contact wire depending on the number of days of exposure. The influence of this film on current collection is thought to be high, though this has not yet been evidenced. Consequently, the authors of this paper conducted exposure tests, measuring the thickness of the film on contact wires, contact-resistance, and numerically simulating thermal conduction, to unravel the unknowns surrounding influence of this film. This paper reveals the influence of the film and proposes a method and cycle for maintenance in the light of these experiment results.
Existing image processing programs for detecting structural damage such as cracks have required the fine-tuning of numerous parameters and experience-based expertise. A method for distinguishing different types of cracks applying deep learning has been developed using tunnel lining images. A classifier was created after learning from a large volume of images in two groups - either with "presence of a crack" or "absence of a crack." The classifier successfully recognized the presence or absence of cracks in images at a rate of more than 90%. Using a color-coded pixelated image to show the position of probable cracks, this paper proposes a hybrid detection method for analyzing cracks with a focus on their location and direction of progress.
Periodic measurement of the structure gauge is essential to ensure safe train operation. Measuring the clearance gauge however, is time and labor intensive given the vast number of trackside facilities. An inexpensive and efficient measuring device using laser range scanners was therefore developed. A management system is also being developed, which maps measured three-dimensional point cloud data to facility data. This paper describes the problems and solutions related to applying the laser range scanners for structural gauging, and presents results obtained from experiments. This paper also describes progress achieved in the development of the management system.
We propose a train operation control system for drawing up operation curves composed of pairs of precise train position and precise operation time, and controlling trains and ground facilities according to the plan. This system realizes more flexible control than that of the conventional system by controlling the on-board device and the ground device according to the train performance curve from the central device, where the management of operations function and the safety control function are integrated. In this report, we describe the control method based on "band" with a margin for safety added to the operation curve, and the requirements for securing safety. In addition, we have confirmed by the simulator that there is no bottleneck in the transmission path, even though the information concentrates on the central device.
When vehicles run through curved sections presenting significant twisting irregularities, the wheel load on the front axle on the outer rail may decrease. Concomitant large lateral force in such cases make it easy for the wheel to climb the rail, increasing the risk of derailment. A new type of bogie has therefore been developed to prevent flange climb derailment by controlling the decrease in wheel load. Confirmation was obtained of the satisfactory basic performance of the bogie through a series of experiments. Confirmation was also obtained of the satisfactory performance of the bogie in the operational running speed range through experiments carried out on the RTRI test line.
The coastal area in the Tohoku region of Japan suffered serious damage from the tsunami caused by the Great East Japan Earthquake in 2011. The purpose of this research is to develop a simulator in order to predict potential damage and put in place disaster prevention measures to protect railway structures against such large scale tsunamis. For this research, a simulation was made of the tsunami generated by the Great East Japan Earthquake to evaluate the damage process that occurred at Shishiorikarakuwa station in Kesennuma city. The tsunami simulator involves a three stage zoom analysis covering a large area from the epicenter to the urban area. The results of the tsunami simulation were then used to conduct a structural analysis of the Shishiorikarakuwa station subject to the tsunami fluid pressure.
Estimation of vehicle dynamic characteristics depends on sufficiently accurate locating of the wheel/rail contact point. However, since it is not possible to place a camera on a truck close enough to the rail head level, locating the wheel/rail contact point while a vehicle is running was not possible in previous studies. To solve this problem, this study proposes a new method for digitalizing the contact point based on the method presented in the study by Burstow et al., which uses thermal imaging. An experiment to locate the contact position was carried out using an actual vehicle on the RTRI test line. The test results confirmed that the contact position between the wheel and the rail could be identified accurately while the vehicle was running in conditions suitable for using a thermography camera. In addition, this paper describes how this proposal could be applied to a derailment experiment.