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SUMMARY:MONITORING\, UNDERSTANDING AND MAINTENANCE OF RAIL DEFECTS ON A EU
 ROPEAN METRO SYSTEM - Dr Stuart Grassie\, RailMeasurement Ltd
DTSTART:20240510T150000Z
DTEND:20240510T160000Z
UID:TALK213397@talks.cam.ac.uk
CONTACT:46601
DESCRIPTION:Rolling contact fatigue (RCF) is one of the main reasons why r
 ails fail prematurely.  Much of the understanding of RCF arose from work a
 t CUED from the late 1970s through to the 1990s.  Although the significanc
 e\, potential dangers and methods to deal with RCF were recognised at that
  time\, measures to treat the problem were not implemented on the UK passe
 nger railway until a fatal derailment at Hatfield occurred in October 2000
 .  The Hatfield derailment changed maintenance practice on passenger railw
 ays worldwide.\n\nSimilar problems exist on metros but there are also sign
 ificant differences.  There are seldom sufficient resources to deal with a
 nd to understand these problems.  These shortcomings were highlighted in t
 he consultancy project described here\, which also took place during the C
 ovid-19 shutdown.  All work was undertaken remotely using photographs\, em
 ail and video-conferencing.  A further complication was a language differe
 nce.\n\nStaff operating the metro in a European capital city noticed that 
 there were apparently severe defects on their heavily used railway.  Novel
  but apparently well-tested equipment had recently been introduced from a 
 well-known supplier.  This equipment had also been “certified” by a ma
 jor European mainline railway and was used worldwide.  Measurements sugges
 ted that defects were more than 7mm in depth over significant lengths of t
 rack.  The common understanding was that if conventional RCF defects of th
 is severity had existed\, continued operation of trains was dangerous as r
 ails could have shattered\, causing trains to derail.  Speed restrictions 
 had been imposed and consideration had been given to halting operations co
 mpletely.  Colleagues who were responsible for the track consulted the aut
 hor for advice on how to proceed and whether\, and if so how\, they could 
 continue to operate trains. \n\nThe seminar presents the problem\, some of
  the measurements that had been undertaken and advice that was given to en
 sure safe running of the railway in the very short and longer terms.  With
 in a couple of months\, rudimentary analysis was undertaken to estimate re
 sidual rail life\, supplemented by laboratory testing of defective rails r
 emoved from track.  It was demonstrated not only that defects were not the
  type of RCF that had been assumed by others\, they were accordingly not a
 n imminent danger.  Moreover\, the equipment that had been introduced to a
 ssess the severity of defects left much to be desired.\n\nSimilar defects 
 exist and continue to be misdiagnosed on many railways of different types.
   London Underground are one of the few metro systems to recognise that th
 ese defects differ from what others accept.  This understanding has saved 
 them a few million GBP annually in the cost of maintenance and premature r
 ail replacement since the late 2000s.\n
LOCATION:JDB Seminar Room\, CUED
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