This study attempts to develop a method for inter-regional train demand estimation considering multi-mode route alternatives. A special effort is made to avoid the path overlapping problem when using logit-type route choice models by adopting the C-logit type model. The characteristics of route choice behavior among multi-mode and single-mode routes are indicated on the basis of the original questionnaire survey data to reveal factors that apply to multi-mode route choice. On the basis of these factors, the modified C-logit type route choice model is applied to route choice behavior of inter-regional passengers to take path overlapping problems in a multi-mode inter-regional transportation network into account. Compared to the classic logit-type model, the developed model has a better performance, a conclusion drawn on the basis of AIC (Akaike's information criterion) and the adjusted likelihood ratio. A sample demand simulation is then conducted to demonstrate how the developed model can be applied in practice. The result indicates that the developed model successfully estimated route choice behavior in a multi-mode inter-regional transportation network.

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Arc discharges increase the mass of the anode in a contact field. However, contact losses decrease the mass of the cathode, which is made of current-collecting materials in a rail field. Conducting careful experiments with the focus on proper changes in arc duration make it possible to notice clear differences among the volumes of the molten material, the surface concave of contact wire on the anode, and the molten-metal bridge. The authors analyzed the differences because the mechanism in the rail field is not the same as that in the contact field but the mechanism is related to the material decrease in the rail field. The Phenomena observed between the anode and the cathode from the start to approximately 10ms during the arc duration can be clarified by taking the aforementioned differences into account. Understanding the phenomena makes it possible to explain the decrease in the current-collecting materials. The paper presents the concave measurement results of the contact wire and the phenomena observed between the electrodes from the start to approximately 10ms during the arc duration.

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Urban mass transit railways suffer from a limitation in that a train's trivial delay caused by passenger congestion is liable to trigger heavier congestion in and delay of other trains; this delay can continue to propagate across the urban mass transit rail network. In practice, the time required for each train operation varies from day to day because elements such as driver's skill, the number of incoming and outgoing passengers, their behavior, the timing of the door operation by a conductor influence each other. Therefore, we constructed a delay propagation model using which a stochastic train simulation can be realized on the basis of the investigation of train delay and the analysis of the factors influencing the delay propagation. Then, we developed an assessment and analysis method of train delay risk. Using the method, we can visualize the delay risk and its originating points within a timetable using the simulation results. Finally, a software program to assist a user in timetable adjustment was implemented. We performed a case study with an aim to reduce delay risk of an actual timetable by using our program. The experimental result suggests that the reduction of delay risk is possible by adjusting the timetable slightly.

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For the updation of contact wire wear detection systems, we have devised cost reduction methods for the wear detection system with optical fiber detection wire. For the field test of Tokaido Shinkansen, the compositions of cost reduction system exhibit good performance. The methods and test results are described in this paper.

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Regenerative energy utilization is expected to be one of the methods of improving the energy efficiency of an electric railway. A system that uses a regeneration inverter to avoid regenerative brake canceling was proposed and realized more than 20 years ago. In a d. c. traction power supply system, in order to verify the effect of a regeneration inverter, a detailed simulation is required. However, a general-purpose tool that realizes such a simulation easily has not yet been developed. In this paper, a simple and unique method to evaluate the amount of regenerative energy on the basis of simple train characteristics is proposed. The proposed approximate evaluation results are compared with practical traction substation data, and their validity is confirmed.

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We have been examining countermeasures to prevent sleepiness during boarding for train drivers. In the year before last, we had measured the environmental variables of a bedroom, which might negatively affect nocturnal sleep. On the basis of these results, we examined the effects of the illumination of the accommodations and nightclothes on nocturnal sleep. In the first experiment, the illumination equipment was changed from white fluorescent lamps to warm color fluorescent ones. In the second experiment, nightclothes were changed from traditional yukatas to other one-piece clothes. The results showed that the onset latency was reduced, and the sleep efficiency increased during nocturnal sleep after changing the illumination equipment. A subjective evaluation of nocturnal sleep showed an improvement when changing nightclothes.

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In Japan, the maximum speed of meter-gauged railway lines (conventional lines) is 160km/h. In recent years, the overhead contact line with a feeder messenger wire, which has the features of labor-saving maintenance and construction cost reduction, has attracted attention. Because further high-speed performance is required, even for meter-gauged railway lines, the development of the overhead contact line with a feeder messenger wire that has excellent high-speed performance is desired. Therefore, compound catenary equipment with a feeder messenger wire has been developed for meter-gauged railway lines. This overhead contact line enables a train to operate at a speed of 160km/h and maintain the features of labor-saving maintenance and construction cost reduction. We performed theoretical analyses and a dynamic-characteristic evaluation to confirm the validity of the overhead contact line. Moreover, we conducted a test run to verify the current collection performance of the overhead contact line.

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One way of reducing the energy consumption of trains is to drive them in an energy-efficient manner. There can be various driving patterns between two adjacent stops, or various speed profiles, because there is a gap called the running time supplement between the planned running time set in a timetable and the shortest possible running time of the train. Previous studies have proposed using up the supplement by changing the driving operation from powering to coasting at optimal points in terms of energy consumption. Others have shown that full use of regenerative braking helps save energy. In this study, we developed an energy-efficient speed profile generator by combining these partial energy-oriented driving approaches when the planned running time is given. We added this generator to existing shortest running time calculation software, so it works for various vehicle and train route data. Numerical experiments showed that our profile provided superior performance compared to manually created ones for artificial and real data.

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This paper discusses non-theoretical harmonics at the DC-side of a 12-pulse rectifier in DC railway systems. These harmonics are the commercial frequency component and the doubled component. The cause of these harmonics are (a) diode forward voltage drop difference, (b) transformer secondary inductance difference, (c) voltage harmonics at the AC-side of the rectifier, and (d) effects of the voltage induced by adjacent high-voltage power transmission lines. We evaluated cases (a), (b), and (c), as case (d) has been previously studied⁽⁴⁾. The results of the evaluation were as follows:  ·The effects of both the transformer secondary inductance difference and the voltage harmonics inside the electric power system are not negligible in some cases on the discussion of the EMC problem among railway equipments.  ·If there are several traction circuits in parallel each of which consists of an input filter, an inverter and several traction motors, the harmonic reduction effect of the filters weakens significantly.

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The introduction of wayside energy storage systems is effective for the recovery of regenerative brake energy in DC-electrified railways. However, considering the cost of their deployment, it is preferable to maximize the energy saving effect with a minimum capacity of the energy storage devices (ESDs). In this paper, we propose a power control method that can improve the energy saving effect while managing the energy of the ESDs. The proposed method is implemented by controlling the filter capacitor voltage of the line side of the power converter for the ESDs depending on their energy and the line voltage of the overhead contact line to which they are connected. Next, the proposed method is verified by numerical simulations and experimental tests with a 1kW class downsized model.

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Monitoring the conditions of railway tracks is essential for ensuring railway safety. In-service vehicles equipped with sensors and a Global Positioning System device can act as probes to detect and analyze real-time vehicle vibration. Such trains are known as “probe vehicles.” Recently, a compact onboard sensing device has been developed. This paper describes a track condition monitoring system that uses a compact onboard sensing device and diagnosis software. The diagnosis software provides the function of detecting track irregularities using the root mean square of the car body's acceleration. It also allows analysis in the time-frequency domain using wavelet transform. A monitoring experiment on a local railway line showed that the system is effective for practical applications.

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The authors have developed a battery-powered dual source EMU (test train) for the purpose of interoperable running from an AC electrified line to a non-electrified line. As the EMU was converted from an existing AC EMU, the rating of the developed battery system (1382V-83kWh) was restricted by the underfloor vacant space. In this paper, we report on the following features and issues of the developed traction circuit: 1) the battery system is directly connected to the DC link of the existing traction circuit without additional power converters, and 2) a low DC link voltage may result in reactive and harmonic components of the collected current. From the results of running tests conducted in JR-Kyushu railway, it is clear that the operational performance of the developed traction circuit and the battery system is sufficient for interoperable service of the EMU.

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From the perspective of railway companies, it is desirable that train operation plans reflect the operational costs. Another important consideration for train operation plans is the requirements of passengers, who expect train services to be more frequent, convenient and reliable. Moreover, growing concerns over power shortage have led to an increased focus on energy saving. Some of these requirements have a trade-off relationship, and thus, it is impossible to fulfill all the requirements. Thus, we need a framework for evaluating various aspects of train operation plans with respect to not only the current plan but also proposed plans. We have developed a simulation system that can simulate interaction among a train diagram, a signaling system, driving patterns between stations and actions of passengers. We have equipped this simulation system with four functions: (1) estimation of increase in dwell time caused by overcrowding, (2) estimation of train delays, (3) calculation of train running time as affected by signal changes under actual running conditions, and (4) calculation of power consumption. We have proposed a method for evaluating train operation plans using the output of these simulation data. Herein, we explain the structure of the developed simulation system and present the results of case studies on the multicriteria evaluation of some train operation plans.

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Various radio communication systems have been used in railway systems such as communication-based train control (CBTC) systems, passenger information service systems, wireless sensor networks, etc. The design and evaluation work involved in constructing the radio communication systems used in railway systems is expensive in terms of time and money in the present circumstances. Thus, for the purpose of facilitating this work, the authors have developed a simulation method to calculate the transmission quality (bit errors, packet loss rates, latency, etc.) taking into consideration the railway-specific environment and usage. This paper outlines the features of a digital radio communication system simulator that calculates transmission quality taking into consideration the railway-specific environment and usage. This paper also shows some examples of simulation results and demonstrates the validity of the simulator.

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A carbon contact strip using rice bran (RB) ceramics has been developed. RB ceramics are porous hard carbon materials that inhibit high wear resistance. In this study, the compliance characteristics of the RB ceramics contact strip and the contact break rate were investigated. The contact strip showed the same compliance characteristics as an existing contact strip and smaller contact break rates. Furthermore, the wear properties of the RB ceramics contact strip and a trolley wire in running tests with actual trains were investigated. The mean wear rate of the RB ceramics contact strip was 2.3 times higher than that of the existing contact strip. The wear rates of trolley wires sliding against the RB ceramics contact strip were approximately the same as those sliding against the existing contact strip, which did not affect the regular maintenance cycles of the trolley wires. On the basis of these results, the RB ceramics contact strip has potential for application as a real-world contact strip.

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The Reliability, Availability, Maintainability and Safety (RAMS) and the Common Criteria (CC) standards have a large number of common requirements that cover highly divergent fields. This is because both are standards relating to the third party certifications of products, the purpose of which is to realize safety and security. Business operators and manufacturers need to comply with increasingly larger numbers of international standards and third party certifications. It is necessary exercise care and avoid inter-standard conflicts, not by complying with each standard, but by devising internal rules that are consistent with all the applicable standards.  This paper takes a bird's-eye view of various international standards, and focuses on the common points of the RAMS and CC standards to help ensure compliance with both of them.

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Train rescheduling during railway operation is a difficult task, and the rescheduling system is expected to support the staff. Previous work suggested a train rescheduling system focusing on passenger delay, but it does not consider train congestion. In this paper, the authors introduce a mathematical model of the change in passenger flow depending on train congestion.

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At present, in Japan, railway signaling systems in which control information is transmitted via rails have been deployed in many applications such as automatic train control (ATC) systems for controlling train speed. Recently considerable R&D has been conducted on digital ATC systems realized by applying digital modulation methods such as minimum shift keying (MSK), and such systems have been installed in some railway lines in urban areas. However, it is difficult to increase the transmission speed owing to the railway noise and the strong attenuation of the track circuit. Therefore the present transmission speed is approximately 300bps. To overcome this problem, we have proposed a new modulation method combining code-division multiple (CDM) and quadrature amplitude modulation (QAM), called the CDM-QAM method. Further we have studied the effectiveness of the CDM-QAM method by conducting computer simulations. In this paper, we developed CDM-QAM transmission devices using digital signal processors (DSPs) and field programmable gate array (FPGA). In addition, we evaluated the performance of the developed devices on the basis parameters such as the bit error rate (BER) characteristics of the measurement environment which was configured to include railway noise.

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Chowarit Mitsantisuk (CMIT) haptics and robotics laboratory focuses on basic and applied research in motion control and mechatronics. The aim of our lab is to develop a novel and efficient human-robot interaction systems to support human activity and to perform task in many application areas, for example medical devices, industrial process and agricultural systems.

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