Safety enhancement was one of the four R&D objectives set out in the 2010-2014 basic plan for research of RTRI, ‘RESEARCH 2010'. This paper introduces three areas related to the latest technologies developed in the course of our research aiming at enhancing railway vehicle-safety. The first introduces results of surveys on failure tendencies of on-board train-protection devices (ATS/ATC) in order to improve reliability of on-board electronic devices . The second is the development of air wipe blowers, designed to increase wheel to rail adhesion in wet conditions . The third area is modeling and evaluation approaches to meet standard value in induction interference tests .
Railway Technical Research Institute has been researching practical technology related to design and construction of railway structures. The principal subjects of the research activity consist of seismic retrofitting, maintenance for previously constructed structures, reduction of construction cost and environmental technologies in railway stations. This review describes the recent trend in structural research, and introduces several examples of the research results and subjects of the research and development in the Railway Technical Research Institute.
RTRI is promoting the fundamental research and development concerning superconducting maglev. The topics of research are high-temperature superconducting magnet, maglev vehicles motion simulation, evaluation of the ground coil and the diagnostic technology of systems. Research on application of maglev technology to the conventional railway system is advanced in cooperation with other organizations. The main topics of this issue are a flywheel energy storage system using superconducting magnetic bearings and a magnetic refrigeration system for air-conditioners. This paper describes the existing circumstance of these researches and developments.
A ‘Virtual Running Test Environment' has been in development, based on Hardware In the Loop Simulation (HILS) technology to emulate, in detail, railway vehicle motion on real tracks. The existing HILS system only reproduces the rigid body motion of a railway vehicle while running. In order to create a more realistic virtual running test environment, trials have been conducted to expand the frequency range of the HILS system to include and evaluate the elastic vibration of railway vehicle carbodies. This paper reports on frequency enhancement of the test equipment and about the construction of the numerical model including reproduction of elastic vibration.
We have converted an existing AC electric multiple unit train (EMU) into a battery-powered and AC-fed dual source EMU (test train) to allow interoperable service between AC electrified lines and non-electrified lines. This paper describes the features and the test results of the developed traction circuit. Results of the on-board battery performance evaluation are also reported, as follows: 1) the running distance, without recharging, of the test train fed by the on-board lithium-ion battery (1382V-83kWh) was approx. 20-30 km, 2) the maximum temperature of the battery was 51.5℃ leaving a sufficient margin before the upper limit of 65℃, 3) the time required for quick charging increases when the battery is in low temperature conditions. The running test results demonstrate that the on-board battery performance is sufficient to permit interoperable services between AC electrified and non-electrified lines.
A crushable lateral displacement stopper has been developed whose gap from the center pin expands only when it receives a strong impact in case of a major earthquake. As a countermeasure to improve the running safety of railway vehicles during earthquakes the stopper is used together with a specialized lateral damper. This paper describes the crushable stopper and results of static load tests and shaking tests on the large shaking test facility of RTRI with a full-scale vehicle model consisting of one bogie and half a carbody.
Fractures in cover concrete on reinforced concrete (RC) viaducts is caused by the expansion of reinforced-bar due to corrosion. In order to understand the mechanisms behind these fractures cross-sections of a corroded rebar were evaluated using the equipment proposed in this paper. In addition, a series of experiments and non-linear finite element analyses were conducted to evaluate the effect of rebar spacing and cover-concrete thickness on the shape of cover concrete fractures and extent of corrosion.
This paper proposes a simple method to evaluate ground-surface waveforms using both the natural period of the ground and waveforms in the engineering bedrock. In this research, the "Equivalent Single Degree of Freedom method" is proposed and is based on the results of static push-over analyses of many grounds with various properties. A comparison was made of waveforms of multi-layered ground, obtained from the proposed method, using dynamic analysis. It was then confirmed that these waves are almost identical, and that the proposed method is applicable to the evaluation of the surface motion. Although information is still lacking about soil properties in regions where there are existing railway lines, proposed method enables economical dense calculation of trackside surface motion. These sets of waveforms will be utilized to identify locations where devastating damage is expected in the case of a strong earthquake.
Cyclic load by train causes subsidence of railway level in tunnels, which is due to ground deformation under roadbed concrete. In consideration of progress of track irregularities and core drilling results, the deformation of the roadbed concrete have been evaluated, but there has been no quantitative inspection method until the present. In this study, to develop a method for quantitative evaluation of train running stability on the slab placed on roadbed concrete, a method to survey roadbed concrete by vibrating it with small-sized and medium-sized vibration exciter was proposed. Vibration characteristic of roadbed concrete with accelerometers fixed near the vibration position was also evaluated. Then the correlation between progress of track irregularities considered to be correlated with the soundness of roadbed concrete and the results of vibration tests was confirmed, and a method for evaluation of the correlation was proposed.
Present air conditioner systems are based on traditional vapor compression technology with usage of HCFC (Hydro Chloro Fluoro Carbon). The Kyoto Protocol has designated HCFC as one of the gases whose emissions are to be reduced. This requires the development of HCFC free systems or the usage of substances which have little greenhouse effect. Under these conditions, magnetic refrigeration technology, which has the potential for high efficiency without Freon gases, has become a focus of attention. The aim of this study is to develop a large-scale magnetic refrigerator which has a maximum kilowatt-class cooling power for air-conditioners mountable on railway vehicles to enable them to be free from Freon gases.
In Japan, regulations on low-frequency magnetic fields came into force. Initial regulations in 2011 applied to power equipment in general, but the scope of regulatory control was expanded in 2012 to cover track-side railway power equipment. Although railway vehicles are not included in the scope of the regulation at the moment, it thought that it is necessary to assess magnetic fields in railway vehicles. As such a series of studies have been launched to develop a method to measure and predict low-frequency magnetic fields in railway vehicles.
Monitoring the temperature inside superconducting magnets is an effective way to detect failures and prevent damage to the magnet. It is possible to measure the multipoint temperatures with one optical fiber sensor thread. The sensor is suitable for measuring the temperature inside cryogenic equipment because of its low heat invasion and high voltage insulation in comparison with the resistance temperature sensors such as CERNOX, thermocouples, etc. However, there have been almost no cases where the optical fiber sensors have actually been used at cryogenic temperature. Investigations where therefore carried out into optical fiber temperature sensors that can be used at cryogenic temperature, to monitor the temperature inside superconducting magnets.