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"Studs": a squat-type defect in rails

Grassie, Stuart L, Fletcher, David I, Gallardo Hernandez, Ezequiel Alberto and Summers, Paul (2011) "Studs": a squat-type defect in rails. Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit , 226 (3). pp. 243-256. ISSN 0954-4097

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In the mid-2000s a rail defect that was classified as a "squat" became increasingly common on London Underground's track. By 2006 there were about 600 of these and they had become the Underground's single most common rail defect. This defect occurred almost exclusively on lines carrying relatively new rolling stock. The work reported here was undertaken initially to characterize this defect, advise as to whether it was indeed a squat and propose a hypothesis that explained its mechanism of formation. The paper includes observations and measurements from track and initial results of metallurgical analysis. The hypothesis for formation of the defects is presented, and both similarities and differences are discussed between these defects and the classical "squat". The defect on London Underground appears to be the same as that described by Marich and his colleagues in Australia and by Li and his colleagues in the Netherlands. It is evidently not a rolling contact fatigue defect. In order to avoid confusion arising from simple misuse of an established term, it is proposed that these defects be given a different name, for which “stud” is proposed. Evidence to date is that the "stud" is a significantly more benign defect than a "squat".

Item Type: Article
Copyright, Publisher and Additional Information: This is an author produced version of a paper accepted for publication in Journal of Rail and Rapid Transit. Uploaded in accordance with the publisher's self-archiving policy.
Keywords: Squat, stud, rolling contact fatigue, rail, pearlitic steel
Institution: The University of Sheffield
Academic Units: The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Mechanical Engineering (Sheffield)
Depositing User: Dr D I Fletcher
Date Deposited: 27 Jul 2011 16:11
Last Modified: 04 Jun 2014 14:54
Published Version: http://dx.doi.org/10.1177/0954409711421462
Status: Published
Publisher: Sage
Refereed: Yes
Identification Number: 10.1177/0954409711421462
URI: http://eprints.whiterose.ac.uk/id/eprint/43163

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