This paper outlines the application of simulation technologies to train operation and signaling systems. It describes the background and the development of simulators in each field. It also describes difficulties encountered with conventional simulators and recent developments aimed at resolving them. The new simulator can reflect interactions between passenger behavior, train movement and the conditions of signaling systems, to obtain more precise simulation results. Finally, it presents a combined technology using the new simulator and the communication network simulator for radio-based train control systems, and its application in the future.
Innovation in railway technology can be achieved through progress in material technology, in terms of the development of the materials themselves, manufacturing processes, higher reliability, etc. Developing material technology is therefore essential for railways. To this end, analytical and mensuration methods are regarded as other basic technology. Today it is also necessary to meet environmental demands, by replacing harmful materials with environmentally acceptable substances, and ensuring that they are energy efficient. This paper describes some of the latest results from research and development into material technology, including the development and application of new materials, and analytical and mensuration methods.
Wayside environmental problems in railways largely involve noise, ground vibration and tunnel micro-pressure wave. This review describes the results of recent studies into these issues conducted by Railway Technical Research Institute.
This study attempts to develop a method for identifying "bottleneck" stations on the inter-regional public transport network. Investing in these bottleneck stations enables the network to be more convenient. First, a method for identifying bottleneck stations on the network was formulated based on multi-objective optimization with a generic algorithm. Second, a system was developed to automatically identify bottleneck stations in a manner which makes them visible. A network outlining the actual inter-regional network in Japan was constructed. The results of numerical experiments on this network suggest that bottleneck stations may be located not only in the metropolitan areas but also in principal cities in the countryside.
When an operational disruption occurs, it is often the case that all trains on that line are suspended. This may significantly decrease services available to passengers, because even passengers who need not go through blocked sections are forced to wait until the cause of the suspension is removed. Deploying additional turn-back facilities and providing shuttle services can localize the negative effect of such disruptions. This research establishes a method for estimating the effectiveness of turn-back facilities from a passenger viewpoint. A series of case studies were compiled, which included experiments to evaluate the effectiveness of additional turn-back services.
This study aims to develop a model of passenger behavior when choosing trains from among various types of train service such as local and rapid services in urban railways, in order to evaluate passenger flows. This paper describes an online survey method for obtaining passenger activity data using departure information display images. A disaggregate demand model was developed for train choice behavior based on the survey data which were collected using the method. The developed model is put into practice by means of an application named "Train-Choice Model Viewer", which can calculate the time series data of passengers' volume at stations and in trains. It makes it possible to simulate the congestion level on each train and in each station when the time schedule is input.
As water is related to many deterioration mechanisms affecting concrete structures, knowledge of water movement behavior in concrete is very useful for the effective maintenance of these structures. In this study, based on many data obtained from monitoring sensors embedded in concrete samples, it was clarified that properties of water penetration into concrete surfaces differ according to component materials, mixing proportions and curing methods of the concrete. It was also made clear that water penetration behavior into the interface between the concrete and the section repair materials depends on pretreatment methods applied before addition of the restoration materials.
This paper describes a fundamental study of the preventive measures against electrical pitting on rolling bearings by using electrically conductive lubricating grease. In order to evaluate the ability to prevent the electrical pitting on rolling bearings of several types of grease into which conductive nanometer-scaled carbon particles, or "nanocarbon" particles, have been dispersed, bearing rotation tests were conducted when an electric current was turned on. It was concluded that the electrically conductive grease has the ability to prevent electrical pitting, or "ridge marks", if the electric current density at the points of rolling contact is lowered.
Elastic rubber materials such as rail pads are used on railway tracks in order to absorb vibrations and impact forces generated by passing trains. For example, rail pads reduce vibrations transmitted through the rails to structural track components such as rail fasteners and track slabs. The performance of rubber materials changes with temperature. Thus, there is a concern that the vibration reduction performance of elastic track materials may decrease at low temperatures because of the higher resulting stiffness. Field tests were conducted at the same point on a concrete viaduct in summer and winter to evaluate the influence of ambient temperature on the vibration and noise reduction performance of elastic track materials. The results showed that vibrations in some structural components under the rail pad increased at low temperature, which agrees with the track theory of the track vibration.
Natural winds are turbulent flows and boundary layers exist near the surface of the actual ground, so that there is a possibility that the aerodynamic forces acting on train/vehicles from natural winds differ from uniform flows. Accordingly, full-scale models of a train/vehicle and a viaduct were constructed in a windy area, and wind characteristics and aerodynamic forces acting on the vehicle models were measured. Wind tunnel tests were conducted to simulate the turbulent boundary layer flow, and these test results agreed well with field tests.
A method has been developed for predicting the aerodynamic noise from the bogie of a high-speed train using a two-dimensional microphone array in a low-noise wind tunnel. First, the flow velocity in the rail direction was measured in a field test at several points along the sleeper direction under the train car. Second, the flow distribution was reproduced precisely in a low-noise wind tunnel. Third, aerodynamic noise generated by the bogie ("aerodynamic bogie noise") was estimated from the noise source distribution measured with a two-dimensional microphone array. Finally, based on the experimental results, the noise generated from the lower part of the car (i.e. the aerodynamic noise estimated through the proposed method and the rolling and machinery noise estimated in a previous study) was compared with field test data measured near the track. The estimated lower part noise levels showed good agreement with those measured in the field test. This suggests that the proposed method is valid for the quantitative estimation of aerodynamic bogie noise. It was also shown that the contribution of the aerodynamic bogie noise is greater than the rolling and machinery noise, especially in the low-frequency region.
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