• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.310-314
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• 2010

Track geometry changes by traffic loads. The bigger the changes are, the worse the riding comfort and running stability of train. This is so-called track irregularity and is the most important quality parameters of ballasted track. To objectively assess track irregularity, track geometry should be able to be measured. Practically, railway companies in Korea use normal distribution as probability distribution of track irregularity. But some countries use non-normal distribution according to their own track recording system. In this report, reviewed probability distribution of Kyung-Bu high-speed line and tested normality.

• 한국강구조학회 논문집
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• 제18권1호
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• pp.47-51
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• 2006

고속철도 궤도검측은 공사관리는 물론, 궤도유지관리 측면에서 매우 중요한 과제이며 향후 유지보수 시 작업계획수립, 작업량산출, 열차속도제한 등 유지보수 시 기본적인 자료로 제공되는 만큼 궤도검측치의 정확성은 매우 중요하며, 이러한 관점에서 국내 궤도검측차(EM-120)의 검측성능과 정확성을 검증하고자 하였다. 본 논문에서는 현재 일반철도구간에 대한 궤도검측 시 사용하고 있는 궤도검측차 (EM-120)의 선형검측자료를 Spectrum 분석한 결과, 파장 1m 부근의 검측치에 Noise가 있는 것을 확인할 수 있었다. 또한 이러한 Noise를 제거하기 위해 Spectrum 분석을 통한 새로운 Filter를 적용한 결과 실제 궤도틀림치에 보다 더 근접한 검측결과를 얻을 수 있었으며 사용기간에 따른 틀림전진 경향 또한 파악할 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.876-879
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• 1996

The vibration of an attractive magnetic levitation(Maglev) vehicle transportation system is caused by the irregularity of the guideway track and the performance of the suspensions of the Maglev system. It is essential for us to give attention to the secondary suspension of the vehicle system as it determines the ride quality. In order to improve the ride quality and running stability, active secondary suspensions have been developed and applied to the vibration problems. This paper analyzes the performance of the active secondary suspension which is applied to an attractive magnetic levitation vehicle system running on a rough track. The dynamics of the suspension system and the optimal control problems are studied. According to the transient and frequency response analyses to the track disturbance, the ride quality of an attractive Maglev vehicle has been improved by applying the designed LQR active controller, and it has been confirmed that this improvement was also influenced by the configuration of the system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(II)
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• pp.104-110
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• 2003

Precast concrete slab track has been already turned out to be more efficient than cast-in place concrete slab track in view of the easiness of construction and the quality control of concrete. Thus, there is a great need to bring in the precast slab track system. In order to develop the realistic precast slab track system that is well conformed to our circumstances, the performance criteria of slab track, and the state-of-the art of precast slab track systems that are used in other countries are briefly discussed here.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.346-353
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• 2005

Track substructure(ballast, subgrade) should have sufficient strength and adequate stiffness to fully support track superstructure(rail, fastener, sleeper). Vertical support stiffness of track comes from the sufficient thickness, adequate strength and stiffness of material of substructure layers. Since the vertical support stiffness of track substructure is closely related with the track geometry, the evaluation of the stiffness is very important to understand the track states. This paper introduces the system, which are composed of Ground Penetrating Radar(GPR), Portable Ballast Sampler(PBS), and Light Falling Weight Deflectometer(LFWD), to evaluate substructure condition and summarizes the field test results performed with the reliable system.

• 한국철도학회논문집
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• 제8권2호
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• pp.111-115
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• 2005

The Study provides the technical background and calculation method f3r the long wave track defect. On high speed railway, It is necessary to manage the long wave band up to 80m track defect fur improving a riding quality. For this reason, Track recording methods for highspeed railway are used 10m and 30m recording bases, these are covered middle wave band and long wave band successfully. Extended base recording data is calculated by geometrical model and this data provides a good result for KTX riding index.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1663-1668
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• 2010

The terms of track is a train-only line for a train service, in premises of station of a station, that the unit over the track for turnout the track from one track to another track, which it changes the course from the main track that is used for operating a train to the side track, is called a turnout The stick strength of tongue rail is adjusting uniform pressure on the both sides, the adhesion strength between a basic rail and tongue rail has to maintain over 100kg of power value to open over 1mm the ends. This study suggested developing a measuring instrument that can measure a basic rail and the stick strength of a movable rail in according with a switch, such as a switch point, and a performance test. This study ties to be helped that it improves measuring usability for the maintainers through improving quality in a stick measuring instrument, that it solves a technique in the site difficulties through improving a measuring instrument, with reducing the obstacles and expenses.

• 한국지반신소재학회논문집
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• 제19권1호
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• pp.45-53
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• 2020

철도분야에서도 계측자료를 바탕으로 머신러닝 기법을 이용하여 예측 분석하는 시도가 점차적으로 증가하고 있는 실정이다. 이 논문에서는 열차의 차상가속도 데이터를 기반으로 궤도의 품질을 결정하는 지표 중에 하나인 궤도품질지수를 머신러닝 기법을 활용하여 예측하였다. 머신러닝 기법으로 활용하고 있는 대표적인 3개의 모델로 궤도품질지수를 예측하여 가장 정확도가 높은 모델은 XGBoost으로 데이터셋에서 85% 이상의 예측정확도를 보였다. 또한 윤축과 대차의 z축의 진동가속도가 고저 궤도품질지수의 기여도가 높은 것으로 나타났으며, 이는 기존 연구결과와도 잘 일치하였다. 이러한 결과를 볼 때 단일 알고리즘인 서포터 벡터머신보다는 앙상블 알고리즘을 적용한 랜덤포레스트와 XGBoost이 정확도가 높은 것으로 판단된다. 따라서 머신러닝 기법에서 적용모델에 따라 정확도가 달라질 수 있기 때문에 차량진동가속도를 이용한 궤도품질지수를 예측하기 위해서는 앙상블 알고리즘을 가지는 모델을 적용하는 것이 적절할 것으로 판단된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.1647-1652
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• 2008

Track geometry consists of tangent and curved lines, which caused undesirable changes in initial track geometry by traffic loads. The bigger the changes are, the worse the riding comfort and running stability of train. This is so-called track irregularity and is the most important quality parameters of ballasted track. To be able to objectively assess track irregularity, track geometry should be able to be measured. Practically, railway companies use moving chord method, this method determine versine values via a chord. The versine is the vertical distance to curve measured in the middle of the chord. This type of method measures only versine of track irregularity curve by transfer function from specific property of measuring tool. In this report, review the characteristics of two types of measuring tools by comparing the measurements. The one is GRP-1000 system, optical surveying system with Total station and lazar prism trolly. This calculates track geometry by surveying absolute coordinates of two points each on both rail heads. The other is Trackmaster, measures versine with 2m of chord length.

• International Journal of Railway
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• 제9권2호
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• pp.27-35
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• 2016

In spite of recent advances in ballasted railway track, the correct choice of ballast for rail track is still considered critical because aggregates progressively deteriorate under traffic loading and environmental exposures. Various ballast requirements, functions and duties have been defined by researchers, railway companies and countries' regulations even though it needs to be integrated to make following proper decision during track operation and maintenance. A proper understanding of ballast properties and suitable tests are prerequisites for minimizing maintenance costs. This paper presents a capable classification for ballast characteristics which need to be investigated beforehand to such a way, firstly to assign ballast functions, secondly need to clarify ballast requirements, thirdly to map appropriate tests to evaluate ballast characteristics and then it must be such that if ballast cannot carry out one of these duties, be able to call there is ballast defect. The paper is structured in order to achieve these objectives.