The optical contact-loss measuring system based on the detection of arcing photons uses visible rays in measurement, which is executed only at night because the method's accuracy is reduced by environmental light. This problem can be solved by adopting a new system based on the detection of ultraviolet rays, which is expected to be adopted by The International Electrotechnical Commission in the future. However, the new system has the drawback of being very expensive. This paper reports on a low-priced measurement system developed to address the issue.

View full abstract

Tension in overhead contact line systems needs to be constant to maintain acceptable levels of current collection. However, it is conceivable that the tension is not exactly constant, because of the resistance at the supporting pulley of messenger wire. In this study, we investigated the mechanism of such resistance, carried out measurement of tension fluctuation, and examined the movement of messenger wires as part the investigation. Furthermore, in order to investigate the influence of the resistance at the supporting pulley on the current collection, we carried out a simulation to ascertain how current collection characteristics are influenced by changes in messenger wire tension.

View full abstract

Recently, electromagnetic environments and electromagnetic compatibility (EMC) in relation to electrical equipment have become important issues. In 2008, the European Union established the EN 50500 standard, which provides measurement and calculation methods for determining magnetic fields emitted from electrical equipment on railways. The major frequency components of the electric and magnetic fields generated from such equipment are in the low range, such as D.C., 16.7 Hz, 50 Hz, 60 Hz and their low-order harmonics. According to the EN 50500 standard, magnetic fields are dominant around this kind of equipment. This paper describes the physical characteristics and analytical methods of low-frequency magnetic fields emitted from electrical equipment in railway substations, and proposes abatement measures and model substation designs based on the above results.

View full abstract

In recent years, the RAMS (reliability, availability, maintainability and safety) international standards have been established, and emphasis has come to be placed on availability as well as safety more than ever before. Accordingly, in order to ensure the targeted availability of railway signalling systems, the authors studied a method of applying measures to such systems from the viewpoint of availability. The results confirmed that it is possible to identify effective measures applicable to the individual pieces of equipment that constitute these systems to attain target values. They also verified the effectiveness of the evaluation method, which involves recognition of status, setting of target values and determination of applicable measures to attain target availability.

View full abstract

In order to identify the characteristics of radio noise emitted from the operation of electric railway systems and evaluate the effects of countermeasures to reduce it, time- and cost-intensive measuring tests are currently necessary. To reduce the amount of time and the costs involved, our institute started a study in 2005 to establish a method of calculating the strength of noise radiated from electric railway systems. As a result of this study, a basic method of determining trends in fluctuations of the strength of radio noise emitted from running electric vehicles has been developed using the moment method. This paper outlines the characteristics of radio noise emitted from electric railway systems and reports on the results of a basic study to establish the calculation method.

View full abstract

Slow-speed-notifying signals are essential safety-related components of railway signal systems. However, if a backup system such as ATS is not installed, the detection of such signals becomes prone to errors as it depends exclusively on the driver's vision. To address this problem, we are developing a system based on an image processing approach that uses a pattern-matching algorithm. This system is able to recognize slow-speed-notifying signals automatically from sequences of images showing the area ahead of the train, then triggers alarms to assist the driver. This paper describes the details of the approach and outlines the results of tests performed with a prototype program.

View full abstract

Twenty years have passed since the phenomenon of high-temperature superconductivity was discovered. Studies have diversified from the stage of basic research, and are now focused on the field of application. At the same time, remarkable progress has been made in the field of high-temperature superconducting (HTS) wire made of rare earth (RE) coated materials featuring high critical current values in environments where temperatures are higher and magnetic fields are stronger than ever. In this context, the Railway Technical Research Institute (RTRI) has started a study on the application of HTS wire to magnets for the Maglev system. In this study, it is important to examine the properties of the wire to be used and reflect them in the design of superconducting magnets. Accordingly, the authors have developed an HTS wire-testing device to evaluate the transport current properties of HTS wire in detail under a range of temperature and magnetic field conditions.

View full abstract

An eddy-current rail brake system is effective in stabilizing the braking ability of trains because its braking force does not depend on adhesion between the wheel and the rail. However, the use of the existing type equipped with DC electromagnets causes the rail temperature to increase, bringing the possibility of rail bending. Because of this, it is impractical for use in Japan. Accordingly, we applied an AC electromagnet (the same as those used in linear induction motors) to the rail brake system to reduce rail temperature rise, and investigated its basic characteristics using a rotary-type test machine.

View full abstract

The RTRI conducted a development of a superconducting magnetic bearing applicable to the flywheel energy storage system for railways. In this study, a high-temperature bulk superconductor (HTS bulk) was combined with superconducting coils to increase the load capacity of the bearing. The flywheel energy storage system has a high energy density, and offers excellent performance in the areas of start/stop operation and load response. However, it has a number of problems in terms of durability and economy. This study aimed to improve driving efficiency by reducing frictional loss and to solve maintenance-related problems by applying superconducting technology to bearing parts. In this paper, we report on the basic study of a magnetic bearing consisting of coupling of superconductors that is applicable as a support bearing for flywheel energy storage systems.

View full abstract