“Security” and “Stability” are an important pair in transport by rail, and to be important with both. Recently railway system supporting this becomes gigantic and becomes complicated. It means that it goes without saying that sensing technology is necessary to move these precisely.
In this paper sensing technologies used for various fields of a railroad are described.

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Railway track is has unique character that it deforms gradually under repetitive train passage. It is no exaggeration to say that track technology is essentially maintenance technology. To maintain sufficient track condition for train running safety and passenger riding comfort, various kinds of inspection are carried with various methods. This paper introduces the state-of-the-art sensing technologies applied for track maintenance. We hope this information will inspire engineers in sensing technology field to develop new application for future track maintenance.

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Nowadays, home-delivery services of packages are imperative in everyday life. These service industries are trying to provide cheaper, faster and safer service. However, package condition and handling during transportation are not disclosed to a customer. In this study, we realized a prototype system by MEMS technology for measuring the environmental conditions around a package for home-delivery service. The system includes barometric pressure, temperature, relative humidity and three dimensional acceleration (shock) sensing devices, as well as an interface circuitry. The system is a size of 115 × 54 × 10 mm³ and a weight of 50 g. We measured the package conditions during the transportation by three Japanese domestic home-delivery services, and using data mining, we were able to obtain a representation of the package's circumstances.

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We have developed a novel railway signal control system using the Internet technology, the system named “Network Signal Control System”. In this paper, we introduce various sensor technologies applied for the signal system. In particular, we have evaluated the system according to the RAMS (Reliability, Availability, Maintainability and Safety) method, and then high reliable data-transmission techniques realized by the popular Internet technology are examined. We also achieve technique to detect missing data by using the “out-of-time flag”, the flag adapted in the data flow. Originally, sensor technologies have significant roles for signal control systems. Several sensing systems are developed and introduced to the signal control system. Moreover, we introduce a novel observation system that is based on the database technology. Server and client system is employed to realize the database, to which every control device transmits its status.
This system has been on service on February 2007. We expect that many sensor technologies will be much useful to improve it.

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Maintenance of railway structures is important. However, the expense and time for inspection of the structures are large. In addition, judgments of performance of the structures depend on experience and knowledge of inspector. Therefore we have applied sensor and information technologies in order to support inspection and to improve inspection and diagnosis technologies.
In this paper, we have shown mechanisms of damage outbreak and performance of sensors for five kinds of structures. Furthermore we have suggested joint-translation-angle detection device, damage detection sensor, FBG (Fiber Bragg Grating) sensor, electric conductible paint and piezoelectric element as self-sensing sensors. In addition, as non-contact transmission system, we have adopted Zig-Bee radio, RF-ID tag and specified low-power radio.
By the completion of those systems, inspection systems of structures which have depended on experience and knowledge of inspector will be extensively improved and precision and certainty for inspection and diagnosis technologies are will be ensured.

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This paper presents automatic speech recognition as one of the most advanced examples in the senso-informatics arena and a new method of statistical multidimensional scaling technique which enables projection of multidimensional statistical models onto visible two-dimensional space. Finally, it is discussed that a speech and sound sensors based on both the speech recognition technologies and the statistical multidimensional scaling method are applicable as practical applications in a railroad field.

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Using Sn-doped single crystal InSb thin films of 1.0μm thickness grown on GaAs substrates by molecular beam epitaxy (MBE), we developed magneto-resistance (MR) elements with very small temperature dependence. These MR elements were used to form a rotation detection sensor combined with a bias magnet. The sensor can achieve the stable contactless detection of rotating gear teeth over a wide range of rotation speeds and a wide range of temperatures -20 to 140°C. The possibility of the angular detection of the rolling railway wheel by the sensor was discussed.

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In this paper, we report on the design, fabrication and characterization of a zinc oxide (ZnO) photoconductive antenna as a sub-terahertz (THz) pulse emitter or detector for time-domain spectroscopy (TDS). A ZnO thin film is deposited by rf magnetron sputtering on a silicon substrate. The resistivity of the deposited ZnO was 9.6×10⁴Ω·cm. The fabricated ZnO photoconductive antennas are evaluated using a TDS measurement system. Photoconductivity of ZnO is obtained using a Ti:Sapphire femto second laser with a wavelength of 775 nm. The bandwidth of the ZnO photoconductive antenna is evaluated to be 1 THz.

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