• Structural Monitoring and Maintenance
• /
• v.4 no.3
• /
• pp.195-220
• /
• 2017

Nowadays, railway system plays a significant role in transportation, conveying cargo, passengers, minerals, grains, and so forth. Railway ballasted track is a conventional railway track as can be seen all over the world. Ballast, located underneath the sleepers, is the most important elements on ballasted track, which has many functions and requires routine maintenance. Ballast needs to be maintained frequently to prevent rail buckling, settlement, misalignment so that ballast has to be modelled accurately. Continuum model was introduced to model granular material and was extended in ballast. However, ballast is a heterogeneous material with highly nonlinear behaviour. Hence, ballast could not be modelled accurately in continuum model due to the discontinuities nature and material degradation of ballast. Discrete element modelling (DEM) is proposed as an alternative approach that provides insight into constitutive model, realistic particle, and contact algorithm between each particle. DEM has been studied in many recent decades. However, there are limitations due to the high computational time and memory consumption, which cause the lack of using in high range. This paper presents a review of recent ballast modelling with benefits and drawbacks. Ballast particles are illustrated either circular, circular crump, spherical, spherical crump, super-quadric, polygonal and polyhedral. Moreover, the gaps and limitations of previous studies are also summarized. The outcome of this study will help the understanding into different ballast modelling and particle. The insight information can be used to improve ballast modelling and monitoring for condition-based track maintenance.

• Journal of the Korean Society for Railway
• /
• v.9 no.5 s.36
• /
• pp.539-543
• /
• 2006

We need to make the standards of maintenance information for urban transit to reduce the cost to maintain the information and to share the information with maintenance workers. It is enable to do systematic maintenance for urban transit by using the information system based on the standardized information. In this paper we propose the major items to standardize and the methods to lay out the standard schemes to enable structured maintenance. We present the 4 items, bill of material, material classification, accident/fault classification, electronic document, to standardize. And we propose how to implement the information system for urban transit based on the standardized information. We describe the implemented information system in two parts; a rolling-stock and an infrastructure part. And also we describe the result of survey to evaluate the system installed at Seoul Metro and Seoul Metropolitan Rapid Transit.

• Journal of the Korean Society for Railway
• /
• v.9 no.5 s.36
• /
• pp.555-560
• /
• 2006

This study finds out and suggests success factors for the application of RIMS project through the case study of Seoul Metro and literature survey. The successful application of RIMS needs expert knowledge and concept of BOM, standardization of maintenance planning, check lists of heavy maintenance inspection, organization structure of rolling stock maintenance offices, material management system of warehousing and the process of parts repairing between offices, connection of material ordering system, problem solving of circular spare parts administration among inspection, maintenance, and material organizational units, systemic serial number management of parts with RFID, daily closing diary connected with work process chart, and sufficient period of RIMS's test run. RIMS contributes to real time management of rolling stock maintenance, transparency of management, reliability of train operation, customer satisfaction, and management innovation.

• Proceedings of the KSR Conference
• /
• 2006.11b
• /
• pp.935-940
• /
• 2006

Present periodic maintenance activities are carried on electric rolling stock in Korea based on predetermined inspection intervals. And this can be seen as a first generation of maintenance techniques without taking into consideration a degree of aging or degradation of the componets. In this study, we have analyzed the current status of maintenance being used in the techniques in various activities such as overseas railway operation organization, and good cases for the advanced country's maintenance system being carried out effectively. Based on the analysis, we would derive implications for efficient application and improvement guidance of maintenance system in electric rolling stock.

• International Journal of Railway
• /
• v.2 no.3
• /
• pp.107-112
• /
• 2009

Research projects of SNCF aim at reducing the costs of infrastructure possessions and improving the operational equipment availability and safety. This permanent search for a better regularity led the SNCF to analyse the maintenance approach of signalling equipment in detail. Until now, it was commonly acknowledged that signalling equipment, which consists of many electronic devices, is not subject to aging. In this study, a Weibull lifetime model, able to describe an aging phenomenon, is used and it can be shown that the deterioration is statistically significant. The validity of the model is tested. We also analyse the influence of environmental covariates. We simulate different scenarios in order to investigate the impact of several maintenance strategies as well as on future maintenance costs, on the amount of components to replace based on the mean age of the network. It can be shown that in most cases a systematic replacement strategy offers the best solution.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.117-124
• /
• 2008

Construction of concrete slab track is trending to increase gradually in national and international for reduction in track maintenance cost and secure of ride comfort. However, in case of railway bridge installed concrete slab track, the serviceability review of end deck should be performed for reducing the maintenance cost of track. The serviceability review of track contains that the compression force which is occurred on fastener of end bridge should be smaller than the compression force causing the deformation limit of elastic pad and the uplift force which is occurred on fastener of end abutment should be smaller than initial fastening force. Therefore, this study calculated the deflection and end rotation of the railway bridge according to the span length and stiffness of railway bridge and estimated the compression force and uplift force which are occurred on the track of end bridge using the finite element method. This study indicated the several diagrams that are contained the correlation between the behaviour of the track and the behaviour of the railway bridge. As a result, to reduce the end rotation of the railway bridge is very efficient to increase the height of railway deck.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.36 no.1
• /
• pp.121-128
• /
• 2016

The restructuring of Korean railway industry, separation of between train operators and an infrastructure manager, had been conducted in 2004 to increase the productivities of railway operations. However, the maintenance-staffs are still employed by Korail (train operator), not by the infrastructure manager, which led the maintenance of railway infrastructure to be conducted by the train operator. The infrastructure manager is now only taking care of financial transferring issues once the train operator requests expenses spent for facility maintenance. Such incomplete restructure may result in a lack of safety performance on railway operations as the roles and responsibilities are less likely to be assigned under the multiple train operators. Thus, this study proposes the way of structuring maintenance divisions and their roles and responsibilities to assure the safe work execution under the circumstance of multiple train operators on the same rail network.

• Journal of the Korean Society for Railway
• /
• v.10 no.2 s.39
• /
• pp.167-178
• /
• 2007

In general, it is known that the concrete ballast track is possible to reduce a cost of maintenance activities cause of maintenance free by restrictive maintenance in application of track ballast structures. However, if deteriorations and fracture mechanism of a material are considered, proper maintenance activities and repairing are continually required. For the problems, we evaluated an economical efficiency of the gravel ballast and the concrete ballast on a proper level of maintenance activities. As the method based on history path is difficult to obtain sufficient reliabilities cause of an absence of real data for maintenance activities, we chose the delphi survey method by professional group, and we obtained the appropriate index and profiles for maintenance activities. As a result, we founded that effects for cost reduction can be expected by preventive maintenance management, and we proposed economical restrictions and life cycle cost for track ballast structures in a life cycle.

• Proceedings of the KSR Conference
• /
• 2003.05a
• /
• pp.126-132
• /
• 2003

Recently with the rapid development in mobile communication, the mobile phone are utilized in many fields of railway system within country and abroad and its use tends to increase continuously. In the railway system, the applicable realm is spreaded to the fields of railway signal communication, railway operating, track maintenance, reservation and information service, also its role is expected to increase. In this thesis, we are surveying the usage application of home and abroad mobile phone in railway system. Studying the present condition of mobile communication in railway system, we are viewing the application plan and the direction of development.

• International Journal of Safety
• /
• v.10 no.1
• /
• pp.36-40
• /
• 2011

Personnel maintaining or repairing the railway tracks or signaling facilities around tracks may experience the sensory disorder when doing maintenance works at the trackside of railway for long time. In this case personnel maintaining at the trackside may collide with the train since they cannot recognize the approach of motor-car although it approaches to the vicinity of maintenance workplace because of the sensory block phenomenon occurred due to their long hours of continued monotonous maintenance work. In order to prevent such motor-car accidents that may occur because railway track workers are unable to recognize the approaching train, the safety alarm equipment is developed to make the approaching motor-car send radio signals and bidirectional detection mechanism between approaching train and trackside personnel. It shows the possibility of utilization in various forms of safety equipment for workers only to the safety helmet to be worn by the maintenance workers while using the configuration of transmitting/receiving sides. In the paper it is represented new alarm equipment, which is the bone-anchored speaker-based safety helmet to be worn by the maintenance workers.