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  • 1.
    Arasteh khouy, Iman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Trafikverket.
    Juntti, Ulla
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Schunnesson, Håkan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Optimisation of track geometry inspection interval2014Inngår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 228, nr 5, s. 546-556Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The measurement and improvement of track quality are key issues in determining the time at which railway maintenance must be performed and its cost. Efficient track maintenance ensures optimum allocation of limited maintenance resources which has an enormous effect on maintenance efficiency. Applying an appropriate tamping strategy helps reduce maintenance costs, making operations more cost-effective and leading to increased safety and passenger comfort levels. This paper discusses optimisation of the track geometry inspection interval with a view to minimising the total ballast maintenance costs per unit traffic load. The proposed model considers inspection time, the maintenance-planning horizon time after inspection and takes into account the costs associated with inspection, tamping and risk of accidents due to poor track quality. It draws on track geometry data from the iron ore line (Malmbanan) in northern Sweden, used by both passenger and freight trains, to find the probability distribution of geometry faults.

  • 2.
    Arasteh khouy, Iman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Trafikverket.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Cost-effective track geometry maintenance limits2016Inngår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 230, nr 2, s. 611-622Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the past, railway maintenance actions were usually planned based on the knowledge and experience of the infrastructure owner. The main goal was to provide a high level of safety, and there was little concern about economic and operational optimisation issues. Today, however, a deregulated competitive environment and budget limitations are forcing railway infrastructures to move from safety limits to cost-effective maintenance limits to optimise operation and maintenance procedures. By so doing, one widens the discussion to include both operational safety and cost-effectiveness for the whole railway transport system. In this study, a cost model is proposed to specify the cost-effective maintenance limits for track geometry maintenance. The proposed model considers the degradation rates of different track sections and takes into account the costs associated with inspection, tamping, delay time penalties, and risk of accidents due to poor track quality. It draws on track geometry data from the Iron Ore Line (Malmbanan) in northern Sweden, used by both passenger and freight trains, to estimate the geometrical degradation rate of each section. The methodology is based on reliability and cost analysis and facilitates the maintenance decision-making process to identify cost-effective maintenance thresholds.

  • 3.
    Arasteh khouy, Iman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Geometrical degradation of switches and crossings on a Swedish heavy haul railroad: a case study2013Inngår i: Proceedings of 10th International Heavy Haul Association Conference, New Delhi, India, 2013, Vol. 1, s. 26-32Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Switches and crossings (S&Cs) are one of the most critical components of railway track systems in terms of safety, operation and maintenance. Each year, a considerable part of the maintenance budget is spent on inspection, maintenance and renewal of S&Cs. However, applying a cost-effective maintenance strategy helps to achieve the best performance at the lowest possible cost. In Sweden, the geometry of S&Cs is inspected at pre-defined time intervals by the STRIX track measurement car. In this paper, time series for the measured longitudinal level of S&Cs on the Iron Ore Line (Malmbanan) in northern Sweden have been used. Two parameters have been defined in this study, namely the absolute residual area (ARa) and the maximum settlement (Smax), to analyse the geometrical degradation of switches and crossings due to dynamic forces generated from train traffic. The paper also evaluates the growth rate of the longitudinal level degradation as a function of million gross tonnes (MGT). The results facilitate correct decision making in the maintenance process through understanding the degradation rate and defining the optimal maintenance thresholds for the planning process. In the long run this will lead to a cost-effective maintenance strategy with optimized inspection and maintenance intervals.

  • 4.
    Arasteh khouy, Iman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Trafikverket.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Geometrical degradation of railway turnouts: a case study from a Swedish heavy haul railroad2014Inngår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 228, nr 6, s. 611-619Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Turnouts are critical components of track systems in terms of safety, operation and maintenance. Each year, a considerable part of the maintenance budget is spent on their inspection, maintenance and renewal. Applying a cost-effective maintenance strategy helps to achieve the best performance at the lowest possible cost. In Sweden, the geometry of turnouts is inspected at predefined time intervals using the STRIX / IMV 100 track measurement car. This study uses time series for the measured longitudinal level of turnouts on the Iron Ore Line (Malmbanan) in northern Sweden. Two different approaches are applied to analyse the geometrical degradation of turnouts due to dynamic forces generated by train traffic. In the first approach, the recorded measurements are adjusted at the crossing point and then the relative geometrical degradation of turnouts is evaluated by using two defined parameters, the absolute residual area and the maximum settlement, In the second approach, various geometry parameters are defined to estimate the degradation in each measurement separately. The growth rate of the longitudinal level degradation as a function of million gross tonnes / time is evaluated. The proposed methods are based on characterisation of the individual track measurements. The results facilitate correct decision-making in the maintenance process through understanding the degradation rate and defining the optimal maintenance thresholds for the planning process. In the long run, this can lead to a cost-effective maintenance strategy with optimised inspection and maintenance intervals.

  • 5.
    Arasteh khouy, Iman
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Schunnesson, Håkan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Juntti, Ulla
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Nissen, Arne
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Evaluation of track geometry maintenance for heavy haul railroad in Sweden: a case study2014Inngår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 228, nr 5, s. 496-503Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The measurement and improvement of track quality are key issues in determining both the restoration time and cost of railway maintenance. Applying the optimal tamping strategy helps reduce maintenance costs, making operations more cost effective and leading to increased safety and passenger comfort. In this paper, track geometry data from the iron ore line (Malmbanan) in northern Sweden, which handles both passenger and freight trains, are used to evaluate track geometry maintenance in cold climate. The paper describes Trafikverket’s (Swedish Transport Administration) tamping strategy and evaluates its effectiveness in measuring, reporting, and improving track quality. Finally, it evaluates the performance of the maintenance contractor and discusses the importance of the functional requirements stated in the outsourcing contracts.

  • 6.
    Asplund, Matthias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Palo, Mikael
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Famurewa, Stephen Mayowa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Condition monitoring of rolling stock wheels: approach towards maintenance decision making2014Inngår i: 27th International Congress on Condition Monitoring and Diagnostic Engineering (COMADEM 2014): 16 - 18 September 2014, Brisbane Convention and Exhibition Centre, Australia, COMADEM International, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Due to the more or less fixed inherent capacity of a railway system, capacity consuming events like failures within a railway network should be kept to a minimum. This could be achieved by the use of existing and new condition monitoring systems which can detect, report and predict failure events in an early stage. Demands for higher service quality, higher capacity, network availability and track quality together with less human intervention on tracks, drive the development of railway condition monitoring systems.Failure driven capacity consumption due to worn or defected rolling stock wheels have a big impact on the capacity and the infrastructure condition. Wheel defects such as out-of-round wheels, generates high forces, and could result in large capacity consumption especially for areas with cold climate conditions. Bad wheels cause even higher track wear that reduce the life length of the track. Wheels with fatigue defects could also influence the track safety issues. This paper presents how different wheel defects can be monitored; together with a review of the most common wayside condition monitoring systems on the Swedish railway network. The study also describes how the decision making process could take advantage of the condition monitoring data in order to increase the achieved network capacity.

  • 7. Chattopadhyay, G.
    et al.
    Hargreaves, D.
    Larsson-Kråik, Per-Olof
    Powell, J.
    Reddy, V.
    Wheatley, N.
    Rail-wheel lubrication: A conceptual decision model2005Inngår i: International Conference on Operations Research Applications in Infrastructure Development in conjunction with the 2005 Annual Convention of Operational Research Society of India (ICORAID-2005-ORSI): 27 December -29 December 2005, India, Bangalore / [ed] V. Chandru; P. Balasubramanian, 2005Konferansepaper (Fagfellevurdert)
  • 8.
    Chattopadhyay, G.
    et al.
    Queensland University of Technology.
    Kumar, Saurabh
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Estimation of parameter for rail degradation2006Inngår i: Condition Monitoring and Diagnostic Engineering Management: COMADEM 2006 ; proceedings of the 19th international congress, Luleºa, Sweden, 12 - 15 June 2006 / [ed] Uday Kumar, Luleå: Luleå tekniska universitet, 2006, s. 605-612Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Rail degradation is a significant problem for rail industries. Wear and fatigue comprises major component of rail degradation. It depends on operational conditions such as train speed, axle load, rail-wheel material type, size and profile, track construction, characteristics of bogie type, Million Gross Tonnes (MGT), curvature, traffic type, weather and environmental conditions. Development of prediction model related to those defects leading to rail breaks and/or rail replacements is vital for economic and safe operation of rail services. Estimation of parameter for failure models is necessary for accurate prediction of expected number of rail defects over a period of time based on Million Gross Tonnes (MGT) traffic, operating conditions and maintenance strategies. This paper focuses on collection and analysis of field data for various defects developed in rail track over a period of time for estimation of parameter for models predicting degradation of rails.

  • 9. Chattopadhyay, G.
    et al.
    Larsson-Kråik, Per-Olof
    Hargreaves, D.
    Reddy, V.
    Modelling and analysis of rail maintenance cost2007Inngår i: International Journal of Production Economics, ISSN 0925-5273, E-ISSN 1873-7579, Vol. 105, nr 2, s. 475-482Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lubrication at wheel flange and rails on sharp curves is considered as an effective solution for reducing wear loss of material from effective cross-section of rail and wheels. Rail administrations around the world have been increasing axle loads and traffic densities in rail networks. This has led to traffic initiated wear, fatigue initiated surface cracks and rail breaks. Limited research has been carried out on the overall impact of combining lubrication strategies and rail grinding. This paper presents a model for lubrication strategy and rail-grinding interval to reduce wear and rolling contact fatigue (RCF). Data from rail industry is collected and used for numerical illustration.

  • 10. Chattopadhyay, G.
    et al.
    Reddy, V.
    Hargreaves, D.
    Larsson-Kråik, Per-Olof
    Assessment of risks and cost benefit analysis of various lubrication strategies for rail tracks under various operating conditions2004Inngår i: Tribologia : Finnish Journal of Tribology, ISSN 0780-2285, Vol. 23, nr 1-2, s. 32-40Artikkel i tidsskrift (Fagfellevurdert)
  • 11. Chattopadhyay, G.
    et al.
    Reddy, V.
    Hargreaves, D
    Larsson-Kråik, Per-Olof
    Rail-wheel lubrication practice: economic comparison for different operating conditions2006Inngår i: Condition Monitoring and Diagnostic Engineering Management : COMADEM 2006: proceedings of the 19th international congress, Luleå, Sweden, 12 - 15 June 2006, Luleå tekniska universitet, 2006Konferansepaper (Fagfellevurdert)
  • 12. Chattopadhyay, G.
    et al.
    Reddy, V.
    Larsson-Kråik, Per-Olof
    Decision on economical rail grinding interval for controlling rolling contact fatigue2005Inngår i: International Transactions in Operational Research, ISSN 0969-6016, E-ISSN 1475-3995, Vol. 12, nr 6, s. 545-558Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Rail players around the world have been increasing axle loads to improve the productivity of freight and heavy haul operations. This has increased the risk of surface cracks at curves because of rolling contact fatigue. Rail grinding has been considered an effective process for controlling these cracks and reducing risks of rail breaks. The complexity of deciding the optimal rail grinding intervals for improving the reliability and safety of rails is because of insufficient understanding of the various factors involved in the crack initiation and propagation process. This paper focuses on identifying the factors influencing rail degradation, developing models for rail failures and analyzing the costs of various grinding intervals for economic decision making. Various costs involved in rail maintenance, such as rail grinding, downtime, inspection, rail failures and derailment, and replacement of worn-out rails, are incorporated into the total cost model developed in this paper. Field data from the rail industry have been used for illustration.

  • 13. Chattopadhyay, Gopi
    et al.
    Hargreaves, Douglas
    Larsson-Kråik, Per-Olof
    Reddy, Venkatarami
    Analysis of field data to develop rail wear prediction model2006Inngår i: Condition Monitoring and Diagnostic Engineering Management : COMADEM 2006: proceedings of the 19th international congress, Luleå, Sweden, 12 - 15 June 2006, Luleå tekniska universitet, 2006Konferansepaper (Fagfellevurdert)
  • 14. Chattopadhyay, Gopi
    et al.
    Hargreaves, Douglas
    Larsson-Kråik, Per-Olof
    Reddy, Venkatarami
    Rail-wheel lubrication practice: framework for lubrication effectiveness2006Inngår i: Condition Monitoring and Diagnostic Engineering Management : COMADEM 2006: proceedings of the 19th international congress, Luleå, Sweden, 12 - 15 June 2006, Luleå tekniska universitet, 2006Konferansepaper (Fagfellevurdert)
  • 15.
    Desai, Ajay
    et al.
    CQ University.
    Chattopadhyay, Gopinath
    CQ University.
    Clegg, Richard
    CQ University.
    Howie, Alex
    QR National Ltd, Brisbane.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Prakash, Braham
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Experimental setup and methodology for the analysis of rail lubricant effectiveness2011Inngår i: Proceedings of the 24th International Congress on Condition Monitoring and Diagnosis Engineering Management: COMADEM 2011 / [ed] Maneesh Singh; Raj B.K.N. Rao; J.P. Liyanage, COMADEM International, 2011, s. 592-598Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Rail and wheel wear is a complex problem. Lubrication plays an important role in reducing wear and enhancing asset life. Curves and switches are the areas of major challenges. Tight curves when running dry shows wear rates higher to rapid wear, increased maintenance costs and non-availability of track due to maintenance or replacement. The economic analysis based on cut-off radius, lubricants and applicators takes a very long time using field data. Rail operators often face difficulties when selecting lubricants. Lubricant manufactures use different test standards when specifying lubricant properties. Four-ball test fails to give a meaningful indication of lubricant performance. The result is often a complex decision problem in ranking different lubricants under a particular axel load. An appropriate selection of lubricant for a particular rail application can give financial returns and extension of asset life. An experimental set up has been proposed in this paper. The experimental results are expected to be used for development of models on effective lubrication. This paper proposes experimental setups and methodology for analysis of lubrication effectiveness in heavy haul lines. Theories along with existing research to date relating to ranking of lubricants for rail applications and a criterion for the ranking is discussed. An analysis is carried out to compare lubricants used in Australian Heavy Haul lines based on manufacturer supplied specifications and experimental results.

  • 16. Frick, A.
    et al.
    Larsson-Kråik, Per-Olof
    Rail grinding operation in Sweden2007Inngår i: European Railway Review, ISSN 1351-1599, Vol. 13, nr 1, s. 69-73Artikkel i tidsskrift (Annet vitenskapelig)
  • 17. Hiensch, M.
    et al.
    Larsson-Kråik, Per-Olof
    Nilsson, O.
    Two-material rail COMBATS rolling contact fatigue2003Inngår i: Railway Gazette International, ISSN 0373-5346, Vol. 159, nr 9Artikkel i tidsskrift (Annet vitenskapelig)
  • 18. Hiensch, M.
    et al.
    Larsson-Kråik, Per-Olof
    Nilsson, O.
    Two-material rail development: Field test results regarding rolling contact fatigue and squeal behaviour2003Inngår i: Proceedings of the Sixth International Conference on Contact Mechanics and Wear of Rail/Wheel Systems: CM2003 / [ed] A. Ekberg; E. Kabo; J.W. Ringsberg, 2003, s. 39-48Konferansepaper (Fagfellevurdert)
  • 19. Hiensch, Martin
    et al.
    Larsson-Kråik, Per-Olof
    Levy, Didier
    Kapoor, Ajay
    Franklin, Francis
    Nielsen, Jens C.O.
    Ringsberg, Jonas
    Josefsson, Lennart
    Two-material rail for RCF and noise control2003Inngår i: Proceedings of the World Congress on Railway Research, 2003Konferansepaper (Fagfellevurdert)
  • 20. Hiensch, Martin
    et al.
    Larsson-Kråik, Per-Olof
    Nilsson, Olof
    Levy, Didier
    Kapoor, Ajay
    Franklin, Francis
    Nielsen, Jens
    Ringsberg, Jonas W.
    Josefsson, B. Lennart
    Two-material rail development: field test results regarding rolling contact fatigue and squeal behaviour2005Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 258, nr 7-8, s. 964-972Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Results from the European 5th Framework project “InfraStar” are presented. The InfraStar project is developing a two-material rail to increase the productivity and reliability of rail infrastructure. The two-material rail aims to be rolling contact fatigue (RCF) resistant and to reduce squeal noise.The InfraStar consortium has built a high level of wheel–rail expertise and understanding regarding RCF initiation and development, level and position of wheel–rail contact forces, and new interface materials and has gained experience in both laboratory and field test operating conditions. Within the project a validated theoretical train–track interaction model and a fatigue design model for two-material rails have been developed.This paper focuses on the field test results of the two-material rail, and how the predictions and expectations from the selection process match with the results observed in track. Results are very promising. The two-material rail prototypes, now over 1 year in track, show no RCF damage where the non-treated rail shows clear RCF damage. The development of the application process and other objectives of the InfraStar project are discussed.

  • 21. Holgerson, Mikael
    et al.
    Rieglert, Jens
    Larsson-Kråik, Per-Olof
    Plough and Stretch Losses for Rolling Ball in Grease1997Inngår i: Proceedings of the fifth International Symposium on Cold Region Development, Anchorage, Alaska, USA, May 4-10, 1997, International Association of Cold Regions Development Studies , 1997, s. 629-632Konferansepaper (Fagfellevurdert)
  • 22.
    Jägare, Veronica
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Söderholm, Peter
    Trafikverket.
    Larsson-Kråik, Per-Olof
    Trafikverket.
    Juntti, Ulla
    Omicold AB.
    Change management in digitalised operation and maintenance of railway2019Inngår i: PROCEEDINGS: International Heavy Haul Association Conference June 2019, 2019, s. 904-911Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Globally, railway is experiencing a major technology transformation (or paradigm shift), triggered by the enhanced utilisation of digital technology. This technological transformation affects not only the technical systems, i.e. railway infrastructure and rolling stock, but also regulations, organisations, processes,and individuals. Hence, hardware, software, but also liveware (i.e. humans) are affected. Today, the digitalisation of railway is characterised by digital services. There are also a range of challenges, e.g. data acquisition,transformation, modelling, processing, visualisation, safety, security, quality, and information assurance. To deal with these challenges, the railway industry needs to define strategies, which enable a smooth transformation of the existing configuration to a digitalised system. Digital railway requires a holistic change management approach based on system-of-systems thinking and a set of appropriate technologies and methodologies. The railway digitalisation strategy should be based on systematic risk management that address aspects of, e.g., information security, traffic safety and project risk. In addition, managing changes for a digitalised railway effectively and efficiently also requires a framework for aspects such as needs finding, requirement identification, and impact of changes for individual, teams and organisation. In this work a major case studywithin the ePilot, has been performed in context of the operation and maintenance processes of the Swedish railway. Therefore, this paper aims to propose a framework for implementing innovations and driving change in a digitalised railway.

  • 23.
    Karim, Ramin
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Birk, Wolfgang
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Cloud-based emaintenance solutions for condition-based maintenance of wheels in heavy haul operation2015Inngår i: 11th International Heavy Haul Conference, (IHHA 2015): 21 – 24 June 2015, Perth, Australia, International Heavy Haul Association , 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Swedish ore line, began in 1898 and was completed and operational by 1902. The line was later electrified and remains so to this day. A study on wheel-rail interaction, to optimize wheel and rail profiles on the Malmbanan and Ofoten lines states that there is a need to develop and apply limit values for the allowable length of single and multiple cracks on wheels. Herein, all stakeholders in the railway organization have to be involved. Provisioning of an integrated decision support system for track and vehicle contributes to increased efficiency and improved effectiveness of the maintenance process, which in turn enables achievement of business excellence. However, an integrated decision support process for maintenance is highly dependent on appropriate information logistics which enables information provisioning to various maintenance stakeholders. One emerging approach for development of eMaintenance solutions is utilization of cloud-based technologies. Cloud-based eMaintenance solutions promises smooth information logistics for maintenance decision support. Hence, the purpose of this paper is to propose an approach for condition-based maintenance decision-making relating to railway vehicle wheels, based on a cloud-based eMaintenance solution. The paper also demonstrates how the proposed approach can be implemented for estimation of Remaining Useful Life (RUL) of railway vehicle wheels.

  • 24.
    Larsson, Roland
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Larsson-Kråik, Per-Olof
    Swedish National Rail Administration, Region North.
    Internet based tribological analyses2002Inngår i: 10th Nordic Symposium on Tribology: NORDTRIB 2000 : Hotel Foresta and KTH, Stockholm, Sweden, June 9-12, 2002, Stockholm: Kungl. Tekniska Högskolan , 2002, s. 147-Konferansepaper (Annet vitenskapelig)
  • 25.
    Larsson, Roland
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Larsson-Kråik, Per-Olof
    Eriksson, Erland
    Sjöberg, Martin
    Luleå University of Technology.
    Höglund, Erik
    Lubricant properties for input to hydrodynamic and elastohydrodynamic lubrication2000Inngår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 214, nr 1, s. 17-27Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The properties of a number of common lubricants have been measured, namely the viscosity, elastohydrodynamic lubrication (EHL) friction coefficient, density, thermal conductivity and heat capacity per unit volume. These properties have been measured within relatively broad pressure and temperature ranges. The lubricants tested were naphthenic and paraffinic mineral oils, blends of these, polyalphaolefins and a polyglycol. Physical--empirical expressions have been developed upon the basis of the measurement results and a number of lubricant constants, or lubricant parameters, have been determined for each lubricant. These expressions can be used in engineering computational tools for lubrication analysis. The use of such analyses is expected to increase into the new millennium and it is thus important to provide reliable and relevant input data

  • 26.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Fullskalig testrigg: förstudie1999Rapport (Annet vitenskapelig)
  • 27. Larsson-Kråik, Per-Olof
    Grease filament formation with circular contact geometry1997Konferansepaper (Fagfellevurdert)
  • 28. Larsson-Kråik, Per-Olof
    Infrastructure Challenges in a Severe Environment: The Swedish Experience2009Inngår i: Guidelines to best practices for heavy haul railway operations: Infrastructure construction and maintenance issues, International Heavy Haul Association , 2009Kapittel i bok, del av antologi (Fagfellevurdert)
  • 29.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Konceptframtagning av testrigg1999Rapport (Annet vitenskapelig)
  • 30. Larsson-Kråik, Per-Olof
    Lubricant drop formation behind an EHD contact1994Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 31. Larsson-Kråik, Per-Olof
    Lubricant replenishment in the vicinity of an EHD contact1996Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Lubricants are subjected to high pressures in many mechanical devices - notably gears, cams, piston rings and rolling element bearings. The contact pressure between the ball and the race in a ball bearing can be as high as 5 GPa. At such high pressures, it is necessary to be able to measure the rheological behaviour of the lubricant in order to obtain input data for computer simulations of rolling and sliding contacts. Lubricant manufacturers are often unable to provide information about the rheology of the lubricant at high pressures, temperatures, shear stresses and shear rates. In paper A, a new Couette rheometer was developed to measure the rheological properties of fluids at pressures up to 500 MPa. The shearrate range covers 0.5 to 20000 1/s and the instrument can operate up to 1O0°C at maximum pressure. The results from the apparatus show excellent agreement with measurements made with a failing ball viscometer on a Newtonian fluid. Criteria for non-laminar flow and viscous heating have been developed for the apparatus to verify that these effects do not significantly influence the measurements. In grease lubricated machine elements the supply of grease to the contact region is very important for long life and maintenance-free operation. For example, in a bearing application the grease is often applied within the housing but outside the bearing. For good lubrication the grease has to move from the storage space into the bearing in order to separate the moving surfaces. One important part of this grease movement is the transport from near the contact region into the rolling track. This transportation mechanism may depend on different phenomena such as: capillary forces, vibrations, drop formation, oil bleeding etc. The papers B-G in this thesis describe investigations of these various phenomena. Papers B-D deal with the drop formation of oils and greases in the outlet of an elastohydrodynamically lubricated contact and how different surface energies can affect the distribution of lubricant between the surfaces. Paper E describes the elongation of grease filaments formed when two surfaces are separating from each other, as a function of time. Measurements of the lift off (adhesion) force acting between the two solid surfaces as a function of time were also made. In paper F a ball and disc apparatus was used to study the replenishment of grease due to side slip. The inlet distance and the 'butterfly' shaped meniscus that surrounds the contact point was studied as a function of the side slip motion of the ball. The filament formation equations from paper E were extended to include the geometry of the butterfly and the inlet distance. Finally, in paper G, four deep groove ball bearings were tested in a SKF R2F test rig to evaluate how lift-off-speed and breakthrough-speed are affected by ball spin. The results are compared to film thickness calculations. The lubricants used were greases, oil bled from the greases and the base oil used for manufacturing the greases.

  • 32. Larsson-Kråik, Per-Olof
    Lubricant replenishment in the vicinity of an EHD contact1998Inngår i: COST 516 Tribology Symposium, Espoo, Finland, 14 - 15 May 1998 / [ed] Helena Ronkainen, Espoo: Technical Research Centre of Finland (VTT) , 1998Konferansepaper (Fagfellevurdert)
  • 33. Larsson-Kråik, Per-Olof
    Managing avalanches using cost-benefit-risk analysis2012Inngår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 226, nr 6, s. 641-649Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Malmbanan, the Swedish Iron Ore Line, runs through rough terrain including high mountains, peat, terraces situated on fjords, and numerous short bridges and culverts. The area is sub-arctic and mountainous, with a sharp gradient between the part with a maritime climate and that with a continental climate. Global warming and new climate conditions are increasing the risk of slab and snow avalanches. A cost-benefit-risk analysis, dealing with slab and snow avalanches, high spring temperatures with fast snow melting, high water levels and heavy rainfalls, was performed in 2001. A number of at-risk sections along the track were identified and some of the risks were later addressed with changes in the infrastructure and changes in train operation during bad weather conditions. During the past 10 years, the various actions taken have been continuously improved. An evaluation based on operational data shows a lower risk of trains running into hazard areas and better control of slab and snow avalanches. Other improvements are better control and monitoring of rock falls and a lowered risk for trains operating during bad weather conditions. The technical systems in use consist of instrumented arrays of poles placed along the track to indicate avalanches. Bridges have been built to permit avalanches to pass under the railway and artificial tunnels have been designed and constructed to allow avalanches to pass over the railway. Rock fall nets have been put into service and professional avalanche inspection teams have been used for risk evaluation during high-risk weather conditions

  • 34. Larsson-Kråik, Per-Olof
    Managing the wheel-rail interface: Railway infrastructure maintenance in a severe environment: The Swedish experience2009Inngår i: Wheel—rail interface handbook, Woodhead Publishing Materials , 2009, s. 633-652Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    This chapter comprises a short introduction to and overview of the challenges that face engineers and researchers working in the field of heavy haul railway operations in a cold climate. If these problems are to be overcome, experts from different engineering disciplines need to work together in order to find solutions for the next generation of heavy haul operation, which will see heavier, longer and faster trains with new train control systems and operating philosophies. Malmbanan runs from the port in Narvik, across the Swedish/Norwegian border via the mines in Kiruna and Malmberget, to the port in Luleå on the coast of the Gulf of Bothnia. The 100 year old ore line runs through rough terrain including high mountains, peat, terraces situated on the fjords in Norway and numerous short bridges and culverts, and part runs above the Arctic Circle. Over the course of its life, the line and its ore traffic have been continuously upgraded. Today 750 m long trains with 30 tonne axle loads are in operation. If cost-efficient operation is to be maintained, engineers must continue to seek new and effective maintenance and operating systems for both infrastructure and rolling stock.

  • 35.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Parallellspår, rundspår: Järnvägsteknisk försöksanläggning1999Rapport (Annet vitenskapelig)
  • 36. Larsson-Kråik, Per-Olof
    Replenishment of grease in a ball and disc apparatus1997Konferansepaper (Fagfellevurdert)
  • 37.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    T2K2, Tunga transporter i kallt klimat: Verksamhetsrapport 1997-09-01 - 1998-09-011999Rapport (Annet vitenskapelig)
  • 38. Larsson-Kråik, Per-Olof
    et al.
    Höglund, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Jonsson, Ulf
    Luleå tekniska universitet.
    Mätning av viskositet och filmtjocklek för två polyalfaolefiner1992Rapport (Annet vitenskapelig)
  • 39. Larsson-Kråik, Per-Olof
    et al.
    Jacobson, Bo
    Luleå tekniska universitet.
    Grease Drop Formation at the Outlet of an EHD Contact1995Inngår i: Proceedings: International Tribology Conference, Yokohama 1995, October 29 - November 2, 1995, ITC '95 / [ed] Makoto Nishimura, Japan Society of Tribologists , 1995Konferansepaper (Fagfellevurdert)
  • 40. Larsson-Kråik, Per-Olof
    et al.
    Jacobson, Bo
    Luleå tekniska universitet.
    Höglund, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Oil drop formation at the outlet of an elastohydrodynamic lubricated point contact1994Konferansepaper (Fagfellevurdert)
  • 41. Larsson-Kråik, Per-Olof
    et al.
    Jacobson, Bo
    Luleå tekniska universitet.
    Höglund, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Oil drop formation at the outlet of an elastohydrodynamic lubricated point contact1995Inngår i: Journal of tribology, ISSN 0742-4787, E-ISSN 1528-8897, Vol. 117, nr 1, s. 74-79Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The loss of lubricant from grease-lubricated bearing surfaces is determined by a number of different mechanisms such as side-flow out of the contacts, evaporation, drop formation, oxidation etc. Some of the drops formed behind a rolling element in a bearing will be onrolled by the next rolling element but some will be lost from the bearing. This loss of lubricant is dependent to a high degree on the speed of the air flow through the bearing and is one of the reasons for early failure of grease lubrication in bearings operating in strong, axial air streams. To evaluate the most important parameters in drop formation, the droplets being thrown out from the outlet of an elastohydrodynamic contact were analyzed using picture processing and statistical methods. An empirical model has been built to describe mathematically the principal factors involved in the volume flow thrown out into the air at the outlet side of the Hertzian contact area. For example, drops in a ball bearing will contribute to the inlet feed of oil for the next ball if it is not lost by sideways flow out from the bearing.

  • 42. Larsson-Kråik, Per-Olof
    et al.
    Jacobson, Bo
    Luleå tekniska universitet.
    Höglund, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Oil drops leaving an EHD contact1994Inngår i: Nordtrib '94: proceedings of the 6th Nordic Symposium on Tribulogy ; 12 - 15 June 1994, Uppsala, Sweden / [ed] P. Hedenqvist, Uppsala, 1994, s. 75-83Konferansepaper (Fagfellevurdert)
  • 43. Larsson-Kråik, Per-Olof
    et al.
    Jacobson, Bo
    Luleå tekniska universitet.
    Höglund, Erik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Oil drops leaving an EHD contact1994Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 179, nr 1-2, s. 23-28Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Many machine elements are lubricated with oil or grease. The flow of lubricant depends on different parameters such as surface roughness, surface energy, temperature, etc. A known problem with rolling bearings is that lubricants have to be refilled more frequently if a gas stream passes through the bearing. It is therefore important to know the behaviour of the lubricant in order to predict, e.g. bearing fatigue life due to a gas stream. By studying the droplets thrown out into the air after passing an elastohydrodynamic contact, the most important parameters for oil drop formation have been determined. The analysis is based on picture processing and statistical methods. The experiments show that an increase in temperature, viscosity or surface velocity will increase the total drop volume. Decreased contact pressure and pure rolling also increase the total drop volume. The volume flow, passing the Hertzian contact area, varied between 18 and 30% of the air born oil-drop flow and it is reasonable to assume that increased flow of air-borne droplets will decrease the film thickness due to insufficient replenishment.

  • 44. Larsson-Kråik, Per-Olof
    et al.
    Jonsson, Ulf
    Luleå tekniska universitet.
    A new high-pressure viscometer1997Inngår i: Tribologia : Finnish Journal of Tribology, ISSN 0780-2285, Vol. 16, nr 3, s. 31-48Artikkel i tidsskrift (Fagfellevurdert)
  • 45. Larsson-Kråik, Per-Olof
    et al.
    Larsson, Roland
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Combined experimental/numerical approach: Influence of different lubricant properties1998Inngår i: 10th ELGI annual general meeting: Eurogrease, European Lubrications Grease Institute , 1998, s. 15-27Konferansepaper (Annet vitenskapelig)
  • 46.
    Larsson-Kråik, Per-Olof
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Larsson, Roland
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Jolkin, Alexei
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Marklund, Olov
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pressure fluctuations as grease soaps pass through an EHL contact2000Inngår i: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 33, nr 3-4, s. 211-216Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Soap lumps entering a grease-lubricated elastohydrodynamic lubrication (EHL) contact were traced as they passed through the contact by using optical interferometry in a standard Ball & Disc apparatus and a high-speed video camera with light enhancer. One specific soap lump could be traced when it was passing through the contact and sharp images of the passing lump could be captured. This paper presents a combined experimental and numerical approach to determine what is happening when such lumps pass through the contact. From the fringe pattern, obtained by optical interferometry, a film thickness map is created by using image processing. This is done for every time step (1 ms) as the lump is passing through the contact. These maps serve as input to a numerical computation of the pressure by assuming elastic deformation theory. Consequently, no assumptions about the rheological behaviour of the grease have to be made. Two greases were studied, based on the same synthetic poly-α-olefin but thickened with Li-12-OH and Li-complex respectively. It is seen that the soap thickened lumps can cause deep elastic indentations accompanied by large pressure fluctuations. The pressure level will in some cases be more than doubled due to lumps entering the contact region. The effects on noise level and operational life are also discussed.

  • 47. Larsson-Kråik, Per-Olof
    et al.
    Nordmark, Thomas
    Managing rail degradation on the Malmbanan2007Inngår i: Railway Gazette International, ISSN 0373-5346, Vol. 163, nr 6Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    An upgrading programme started in 1998 and due to be completed by 2010 is allowing the introduction of heavier axleloads on Sweden's heavy haul iron ore line, permitting gross train weights to be increased to more than 8 000 tonnes. But the transition requires careful management if degradation of the infrastructure is to be kept under control

  • 48.
    Lindsund, Isabelle
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Palo, Mikael
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Potential reliability improvements for SSAB railway transport2012Rapport (Annet vitenskapelig)
  • 49.
    Morant, Amparo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Gustafson, Anna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Söderholm, Peter
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Safety and availability evaluation of railway operation based on the state of signalling systems2017Inngår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 231, nr 2, s. 226-238Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A framework is presented to evaluate the safety and availability of the railway operation, and quantifying the probability of the signalling system not to supervise the railway traffic. Since a failure of the signalling systems still allows operation of the railway, it is not sufficient to study their effect on the railway operation by considering only the failures and delays. The safety and availability are evaluated, handling both repairs and replacements by using a Markov model. The model is verified with a case study of Swedish railway signalling systems with different scenarios. The results show that the probability of being in a state where operation is possible in a degraded mode is greater than the probability of not being operative at all, which reduces delays but requires other risk mitigation measures to ensure safe operation. The effects that different improvements can have on the safety and availability of the railway operation are simulated. The results show that combining maintenance improvements to reduce the failure rate and increase the repair rate is more efficient at increasing the probability of being in an operative state and reducing the probability of operating in a degraded state.

  • 50.
    Morant, Amparo
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Karim, Ramin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Larsson-Kråik, Per-Olof
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Information logistics for maintenance of railway signalling systems: A case study2013Inngår i: The international Journal of railway technology, ISSN 2049-5358, E-ISSN 2053-602X, Vol. 2, nr 2, s. 97-112Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of this paper is to explore the use of information logistics for railway signalling systems to improve the efficiency of their corrective maintenance. The signalling system is used to control, supervise and protect railway traffic; therefore, its reliability, maintainability and related maintenance support affect the availability of the railway network. The paper reviews the current status of the maintenance of railway signalling systems, looking at company surveys and company data for a specific case study and consulting relevant literature. It describes how and where data are processed and analyses corrective maintenance work orders to determine how much time is spent on corrective action and knowledge management Areas of improvement are identified and possible improvements are proposed. The efficiency of information logistics has a clear effect on the dependability of the railway signalling system. Signalling systems’ performance can be improved by having better control of and accessibility to the information required for each maintenance action.

12 1 - 50 of 64
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