Editorial

21st Century Rails

I have always had an interest in railways. As a young boy I often could be found train spotting on Sheffield’s Midland and Victoria stations and today when fishing at Pickering Beck I always stop and look as Sir Nigel Gresley and the other trains of the North Yorks Railways steam past. Gone are the steam trains from the mainlines, except for the occasional outings of engines such as Tornado, to be replaced with nondescript high speed trains, but I still have an interest in the infrastructure, the upgraded Victorian and Edwardian stations and, especially, the track.

This interest in the track is a consequence of my involvement in a number of projects on rail steel developments during over forty years of working in R&D in the fields of secondary steelmaking and continuous casting for British Steel and Corus. Due to a family bereavement, during the summer and autumn of 2011, I had to make many journeys by rail between home and London. It was on a number of these, when the train stopped for incidents on the line or moved slowly through engineering track works, that it was possible to note the condition of the track with respect to rail head wear and shape, rolled in debris and, very occasionally, rail head cracking. It left me wondering how far new rail steel grades had been developed, and what was the progress on in-situ crack measurement and rail rectification since my retirement from Corus. Thus, it was of great interest that I attended the Institute of Materials, Minerals and Mining conference on 21st Century Rails, held in November 2011 at the National Rail Museum in York.

With increasing passenger numbers and some rail lines near, or at full capacity at peak times with respect to train units, track downtime for rail replacement or in-situ rectification is at a premium. Thus, the driver for rail grade development over the past 20 years has been harder, more wear resisting rails supplied in longer lengths to reduce the number of thermit welded joints over a given length of track. It was a disappointment therefore that only one paper from Tata Steel Europe described new rail grade developments.

Rail travel is very safe, less than one fatal accident per billion train kilometres, each year since 2002. The last fatal rail accident caused by rail failure was Hatfield in 2000 and this has been described as the UK’s most expensive rail accident because the cause, transverse fatigue cracking of the rail and known to exist in many parts of the network at the time, resulted in a significant slowing of trains whilst miles of track were replaced. In 2001, nine hundred and forty nine rail breakage incidents were reported, but this was reduced to one hundred and seventy by 2008, mainly as a consequence of much of the research and development activity and increased track monitoring done since Hatfield.

Over the long term, the consequence of rail wheel contact is the deformation of the rail head and work hardening of the rail head surface and sub-surface regions. Heavy deformation of the rail head can lead to rolling contact fatigue (RCF), which when light can be removed by grinding at the same time as when re-profiling the rail head. Research into the development of an understanding of the formation of RCF and its detection and removal by grinding in-situ has been significant since the years since Hatfield, with much fundamental work being done in the UK’s universities. Three such papers from the University of Birmingham are published in this special edition of Ironmaking and Steelmaking; ‘Measurement and modelling of the AFCM response to multiple RCF cracks in rail and wheels’; ‘Use of misorientation values to further understand deformation in rail steels’; and, ‘Detection of crack growth in rail steel using acoustic emission’.

RCF can be limited by the selection of suitable premium quality rail steels where it is known to be a significant problem, such as the outside rail on tight curves. The experience of Network Rail in this respect is given in the paper ‘Experience of premium grade rail steels to resist rolling contact fatigue (RCF) on GB Network’, published in this edition. In addition to selecting premium quality rails, track lubrication for friction control may be applied on tight curves; this was discussed in the paper ‘Rail grade selection and friction management: a combined approach for optimising rail–wheel contact’, published in this edition.

Re-profiling of the rail head in-situ is now common practice on the rail network, as well as on the town and city tramway networks. The topic was covered in a number of papers at the conference and one paper from Network Rail ‘Managing rail profile’ is published in this special edition.

Finally, this edition also includes a substantive report on the conference.