Surface/ground water pollution caused by the inflow of acid water enriched with heavy metals poses a serious environmental problem around excavation sites where sulfide minerals chemically decompose. To establish a method to evaluate acid water drainage from rock, we examined the percolation and geochemical characteristics of rock. It became clear that it was possible to evaluate acid water drainage by using the following indices; (1) the pH value one hour after a batch-leaching test; (2) the rock's sulfur content; and (3) in the case of mudstone only, the S/Ca mole ratio of the rock.

View full abstract

Rockfall countermeasures are very important for maintaining safe and reliable rail transport operations. The authors have recently developed a simple rockfall protection fence, which consists of component materials in general use and unique flexible mesh nets that can withstand deformation. This paper deals with the fundamental tests of the fence components and full-scale test procedures. Through systematic full-scale tests, efficient combinations of fence components and foundations were found.

View full abstract

Although computer systems can assist rescheduling experts and have recently been utilized to restore disrupted train operations, they are not so helpful in decreasing dispatcher workloads. This is because they lack the intelligence that would enable them to create rescheduling plans automatically. In this paper, we propose an algorithm for automatic train rescheduling. Firstly, we proposed using the causes of passenger dissatisfaction as rescheduling plan criteria and to regard the problem of train rescheduling as a constraint optimization problem in which the degree of passenger dissatisfaction should be minimized. Then we introduced an algorithm for train rescheduling designed as a combination of Program Evaluation and Review Technique (PERT) and metaheuristics. We have shown some experimental results derived from applying the algorithm to data from existing train schedules.

View full abstract

We studied a method of using a portable terminal to input inspection data into a facility management database and undertook research into a prototype data entry system that uses a cellular phone and a Personal Digital Assistant (PDA), applying speech recognition and a method to automatically identify facilities with radio frequency identification (RF-ID) tags. In addition, we conducted research into methods that would enable inspection data entry even in areas where electric wave is interrupted and an e-mail question answering system that facilitates manual information retrieval and simple fault diagnosis is under development. This paper describes the research results concerning the use of the portable terminal.

View full abstract

The rail/wheel rolling contact affects the microstructure of rail steel in the surface layer of rail. The microstructure was investigated from a point of view of the crystal orientation by means of X-ray inverse pole figure measurement and EBSP analysis. The specific condition that the {111} crystallographic plane of the constituent grains is oriented in parallel to the running surface in the surface layer of a rail used in service for 16 years is confirmed through the analysis of X-ray inverse pole figure and EBSP orientation image map. The degree of orientation evaluated by the axis density of the 111 crystallographic axis varies in the direction of depth from the running surface giving a maximum at about 100 μm from the surface. Based on the results, it is conceivable that the 111 axis density could be a potential parameter to evaluate the degree of rolling contact damage accumulated in the surface layer of used rails.

View full abstract

The cycle of induction motor disassembly inspections depends on the durability of the grease, which is the least durable of all the bearing parts and materials used at present. It is therefore highly desirable to extend grease service life. To meet such requirements, a number of studies were made into grease pocket structures, which concluded that an improvement in structure was essential as grease pocket shapes have a direct relationship on grease lubrication effectiveness. A laboratory test under static conditions was performed with small grease pocket models of different shapes to formulate a grease pocket design guideline.

View full abstract

For prediction of the micro-pressure wave, which is one of the environmental problems in high-speed railways, it is necessary to clarify the distortion mechanism of the compression wave propagating through a tunnel. In this study, field measurement and numerical simulation were performed to investigate the distortion of the compression wave generated by a train entering a tunnel as it propagated through the tunnel. The field measurement was performed in a Shinkansen slab-tracked tunnel of 26 km in length with side branches, which was the longest mountain tunnel in the world as of 2004. The pressure of the compression wave was measured at 12 locations in the tunnel. In the numerical simulation, the distortion of the compression waveform was calculated by one-dimensional compressible flow analysis taking into account steady and unsteady friction on the tunnel wall and by acoustic analysis on the effect of side branches. The results of the numerical simulation agreed well with those from the field measurement and clarify the distortion process of the compression wave during its propagation in the tunnel with slab tracks.

View full abstract

If a tunnel is to be constructed in an urban area, it is often necessary to predict the vibration and structure-borne sound levels in nearby buildings. Establishing a method for this purpose necessitated a detailed investigation of the propagation properties of train-induced vibration from tunnels to the ground surface. Therefore, we measured the vibration levels both on and under the ground surface, as well as that of a tunnel structure located at the same site. The results of the measurements were compared with those from numerical analysis to confirm the adequacy of the analysis method.

View full abstract

In order to investigate the effects of train vibrations on laptop personal computers (PC) and their users, a survey was carried out and related experiments were subsequently conducted. The survey, which involved 114 computer users, was undertaken to identify cabin limitations and to ascertain needs from the PC users. The results indicated that the majority of those who took part in the survey were not satisfied with the current size or adjustability of seat tables provided in the cabin. Based on the user survey results, experiments were performed to ensure an optimum working space for PC use on running trains. The subjects (participants) evaluated various setting positions while performing tasks on PCs in a train simulator. The simulation results indicated ideal lengths, positioning, and an optimum range for seat table adjustability. The importance of providing adequate table space between PC and its user was also confirmed.

View full abstract

Railway companies have adopted various measures to minimize annoying passenger behavior. Questionnaire and monitor surveys conducted on railway station users in core cities confirmed that the degree of awareness is high in the case of "soft" measures such as making announcements or putting up posters in trains or at stations. Depending on the type of annoying behavior and passenger attributes, there are differences in what passengers expect from the measures taken by railway companies. For some ill-mannered passengers, posters including data are more effective than conventional illustrations.

View full abstract