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Wayside Condition Monitoring System for Railway Wheel Profiles: Applications and Performance Assessment
Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The railway is an important mode of transport, due to its environmental friendliness, high safety level, and low energy consumption combined with a high transport capacity, among other factors. The Swedish railway network is old, there has been almost no expansion of the network during the past few decades, and more traffic is expected. Therefore, there is currently a demand for more track capacity and, in the short term, the existing network is expected to deliver the increased capacity. The railway operators in the network have a large impact on train delays, and wheel failures are one large contributor of delays. Delays destroy capacity and, therefore, capacityconsuming failures, such as abnormal wheels, need to be minimised. This can be achieved by using appropriate condition monitoring for the wheels on the track to find potential capacity consumers before failures happen. Therefore, the condition of the wheel-rail interface is important, since the state of the wheel influences that of the rail and vice versa. The monitoring of rail profiles is already being performed, but the monitoring of wheel profiles is still in the development phase. This thesis treats the applications and performance assessment of a wheel profile measurement system (WPMS), and presents case studies focusing on its system and measurement performance. The proposed applications concern how the information from the WPMS can be integrated with information from other data sources and with physical models to obtain a true current picture of the wheel behaviour. The thesis investigates the measurement performance of the WPMS by using a paired T-test and a number of quality measures, e.g. the reproducibility and repeatability, the precision-to-tolerance ratio and the signal-to-noise ratio. In conclusion, this thesis shows that the WPMS works well with an expected level of reliability in a harsh climate with respect to its measurement and system performance. By combining other data with the data from the WPMS, potentially abnormal wheels can be found in an early stage if the proposed new maintenance limit for the wheel parameter of the flange height is implemented. Furthermore, through adding a physical model to the process, the real contact condition of the actual wheel-rail interface can be evaluated and measurement deviations can be found. However, the wheel parameters, as well as the entire profile, need a high measurement quality with little variation, which seems to be an issue with respect to the measurement performance when advanced calculations are to be done. Therefore, a new approach for evaluating measurement performance has been developed using established statistical tools and quality measures with predefined acceptance limits; with the help of this approach, one can differentiate between the variation in the measurements originating in the different measurement units and the variation originating in the wheels. This new approach can be applied to judge the measurement performance of wheel profile condition-monitoring systems, and can also be implemented for other condition-monitoring systems to evaluate their measurement performance. Finally, this approach promotes the development of a condition-based maintenance policy by providing more reliable information for maintenance decision makers.

Place, publisher, year, edition, pages
Luleå tekniska universitet, 2016.
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
National Category
Infrastructure Engineering
Research subject
Operation and Maintenance
Identifiers
URN: urn:nbn:se:ltu:diva-60146ISBN: 978-91-7583-745-1ISBN: 978-91-7583-746-8 (pdf)OAI: oai:DiVA.org:ltu-60146DiVA: diva2:1044611
Public defence
2016-12-15, C305, Luleå tekniska universitet, 10:00
Supervisors
Available from: 2016-11-08 Created: 2016-11-04 Last updated: 2016-11-24Bibliographically approved
List of papers
1. Reliability and measurement accuracy of a condition monitoring system in an extreme climate: a case study of automatic laser scanning of wheel profiles
Open this publication in new window or tab >>Reliability and measurement accuracy of a condition monitoring system in an extreme climate: a case study of automatic laser scanning of wheel profiles
Show others...
2014 (English)In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 228, no 6, 695-704 p.Article in journal (Refereed) Published
Abstract [en]

The Iron Ore Line (Malmbanan) is a 473 km long track section located in northern Sweden and has been in operation since 1903. This track section stretches through two countries, namely Sweden and Norway, and the main part of the track runs on the Swedish side, where the owner is the Swedish Government and the infrastructure manager is Trafikverket (the Swedish Transport Administration). The ore trains are owned and managed by the freight operator and mining company LKAB. Due to the high axle load exerted by transportation of the iron ore, 30 tonnes, and the high demand for a constant flow of ore and pellets, the track and wagons must be monitored and maintained on a regular basis. The condition of the wagon wheel is one of the most important aspects in this connection, and here the wheel profile plays an important role. For this reason an automatic laser-based wheel profile monitoring system (WPMS) has been installed on this line using a system lifecycle approach that is based on the reliability, availability, maintainability and safety (RAMS) approach for railways. The system was prepared and installed and is being operated in a collaborative project between the freight operator and infrastructure manager. The measurements are used to diagnose the condition of the wheels, and to further optimize their maintenance. This paper presents a study of the concepts and ideas of the WPMS, and the selection, installation and validation of the equipment using a system lifecycle approach that is based on RAMS for railways. Results from the profile measurements and validation are shown. The system’s reliability during performance in extreme climate conditions, with severe cold and large quantities of snow, is presented. Then the benefits, perceived challenges and acquired knowledge of the system are discussed, and an improved V-model for the lifecycle approach is presented.

Research subject
Operation and Maintenance
Identifiers
urn:nbn:se:ltu:diva-7929 (URN)10.1177/0954409714528485 (DOI)65d03b0f-3fc8-4d1a-85b2-8aa7bf544ba0 (Local ID)65d03b0f-3fc8-4d1a-85b2-8aa7bf544ba0 (Archive number)65d03b0f-3fc8-4d1a-85b2-8aa7bf544ba0 (OAI)
Note
Validerad; 2014; 20140422 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2016-11-04Bibliographically approved
2. Evaluating the measurement capability of a wheel profile measurement system by using GR&R
Open this publication in new window or tab >>Evaluating the measurement capability of a wheel profile measurement system by using GR&R
2016 (English)In: Measurement, ISSN 0263-2241, E-ISSN 1873-412X, Vol. 92, 19–27- p.Article in journal (Refereed) Published
Abstract [en]

Reliable data with less variation play a key role for acceptance of the usefulness of the measurement output of a wheel profile measurement system (WPMS) in a railway network. However, in practice, most studies are carried out without checking the reliability of data from such a system, which may lead to inappropriate maintenance strategies. To ensure the measurement capability of WPMS and to support robust maintenance in railway systems, this study has evaluated measurement data for the flange height, flange thickness, flange slope, and tread hollowing of rolling stock wheels by using gauge repeatability and reproducibility (GR&R). In this study, acceptance and rejection criteria for the precision-to-tolerance ratio (PTR), signal-to-noise ratio (SNR), and discrimination ratio (DR) have been employed to evaluate the measurement capabilities. For the purpose of illustration, we have implemented a new proposed approach. This approach involves both an analysis using graphs with four regions with a confidence interval (CI) of 95% and an analysis using a graph with three regions with only the predicted values; the latter type of graph represents an innovation made in this study. The results show that the measurements of the tread hollowing and flange slope are on an acceptable level, while those for the flange height and flange thickness have to be rejected as unacceptable. The action proposed to increase the quality of data on the flange height and flange thickness is to enhance the calibration of the WPMS. In conclusion, GR&R is a useful tool to evaluate the measurement capability of WPMS and to provide helpful support for maintenance decision making.

Abstract [en]

Reliable data with less variation play a key role for acceptance of the usefulness of the measurement output of a wheel profile measurement system (WPMS) in a railway network. However, in practice, most studies are carried out without checking the reliability of data from such a system, which may lead to inappropriate maintenance strategies. To ensure the measurement capability of WPMS and to support robust maintenance in railway systems, this study has evaluated measurement data for the flange height, flange thickness, flange slope, and tread hollowing of rolling stock wheels by using gauge repeatability and reproducibility (GR&R). In this study, acceptance and rejection criteria for the precision-to-tolerance ratio (PTR), signal-to-noise ratio (SNR), and discrimination ratio (DR) have been employed to evaluate the measurement capabilities. For the purpose of illustration, we have implemented a new proposed approach. This approach involves both an analysis using graphs with four regions with a confidence interval (CI) of 95% and an analysis using a graph with three regions with only the predicted values; the latter type of graph represents an innovation made in this study. This graph has the advantages that it can visualize three different levels of data quality in same figure, namely “unacceptable”, “acceptable” and “good”, and also include a number of measures without becoming unclear, which are features that have been missing in previous presentations. The results show that the measurements of the flange slope are on an acceptable level, while those for the flange height, flange thickness and tread hollowing have to be rejected as unacceptable. The action proposed for increasing the quality of data on the flange height, flange thickness and tread hollowing is to enhance the calibration of the WPMS. In conclusion, GR&R is a useful tool to evaluate the measurement capability of WPMS and to provide helpful support for maintenance decision making. This investigation also shows that there is good reason to be careful when selecting measures and when interpreting the results, since, for a certain wheel profile parameter, when one measure is used, the results may be acceptable, but when another measure is used, the results may be unacceptable.

Research subject
Operation and Maintenance
Identifiers
urn:nbn:se:ltu:diva-9409 (URN)10.1016/j.measurement.2016.05.090 (DOI)000380736700003 ()8062b662-b2f7-4a53-9365-fe7966466b08 (Local ID)8062b662-b2f7-4a53-9365-fe7966466b08 (Archive number)8062b662-b2f7-4a53-9365-fe7966466b08 (OAI)
Note

Validerad; 2016; Nivå 2; 20160403 (matasp)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2016-11-04Bibliographically approved
3. A study of railway wheel profile parameters used as indicators of an increased risk of wheel defects
Open this publication in new window or tab >>A study of railway wheel profile parameters used as indicators of an increased risk of wheel defects
2016 (English)In: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 230, no 2, 323-334 p.Article in journal (Refereed) Published
Abstract [en]

The capacity demands on the railways will increase in the future, as well as the demands for a robust and available system. The availability of the railway system is dependent on the condition of the infrastructure and the rolling stock. To inspect the rolling stock and to prevent damage to the track due to faulty wheels, infrastructure managers normally install wayside monitoring systems along the track. Such systems indicate, for example, wheels that fall outside the defined safety limits and have to be removed from service to prevent further damage to the track. Due to the nature of many wayside monitoring systems, which only monitor vehicles at definite points along the track, damage may be induced on the track prior to fault detection at the location of the system. Such damage can entail capacity-consuming speed reductions and manual track inspections before the track can be opened for traffic again. The number of wheel defects must therefore be kept to a minimum. In this paper wheel profile parameters measured by a wayside wheel profile measurement system, installed along the Swedish Iron Ore Line, are examined and related to warning and alarm indications from a wheel defect detector installed on the same line. The study shows that an increased wheel wear, detectable by changes in the wheel profile parameters could be used to reduce the risk of capacity-consuming wheel defect failure events and its reactive measures.

Research subject
Operation and Maintenance
Identifiers
urn:nbn:se:ltu:diva-11827 (URN)10.1177/0954409714541953 (DOI)ad81ec6f-eb97-4226-a5fd-9b81eb39b186 (Local ID)ad81ec6f-eb97-4226-a5fd-9b81eb39b186 (Archive number)ad81ec6f-eb97-4226-a5fd-9b81eb39b186 (OAI)
Note
Validerad; 2016; Nivå 2; 20131210 (matasp)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2016-11-04Bibliographically approved
4. Assessment of the data quality of wayside wheel profile measurements
Open this publication in new window or tab >>Assessment of the data quality of wayside wheel profile measurements
2016 (English)In: International Journal of COMADEM, ISSN 1363-7681, Vol. 19, no 3, 19-25 p.Article in journal (Refereed) Published
Abstract [en]

To evaluate the behaviour and the condition of a railway wheel in relation to performance and safety criteria, the wheel profile can be measured. This can be achieved using manual methods or automatic systems mounted along the railway track. Such systems have the advantage that they can measure a vast number of profiles, enabling new possibilities of performing statistical analyses of the results and pinpointing bad wheels at an early stage. These wayside measurement systems are, however, subjected to different environmental conditions that can affect the data quality of the measurement. If one is to be able to use automatic wheel profile measurements, the data quality has to be controlled in order to facilitate maintenance decisions. This paper proposes a method for the data quality assessment of an automatic wayside condition monitoring system measuring railway rolling stock wheels. The purpose of the assessment method proposed in this paper is to validate individual wheel profile measurements to ensure the accuracy of the wheel profile measurement data and hence the following data analysis. The method consists of a check routine based on the paired t-test, which uses a hypothesis test to verify if the null hypotheses are true. The check routine compares measurements of passing wheels rolling to a certain destination with measurements of the same wheels returning from that destination. The routine of comparing measurements of the same wheel, which is performed by four sensors (one on each side of each rail), will ensure that the sensors generate the same data for the same sample. A case study is presented which shows how the method can detect a faulty setup of the measurement system and prevent incorrect interpretations of the data from different measurement units in the same system. The paper ends with a discussion and conclusions concerning the improvements that are presented.

National Category
Other Civil Engineering
Research subject
Operation and Maintenance
Identifiers
urn:nbn:se:ltu:diva-10887 (URN)2-s2.0-84987680545 (ScopusID)9c3cbb22-ce80-4a35-8f12-e4f456f6a51b (Local ID)9c3cbb22-ce80-4a35-8f12-e4f456f6a51b (Archive number)9c3cbb22-ce80-4a35-8f12-e4f456f6a51b (OAI)
Note

Validerad; 2016; Nivå 1; 2016-10-26 (inah)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2016-11-04Bibliographically approved

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