© Pavlov & Partners '04

  We would like to present the latest technology of rail head surface hardening that allows to extend operational life of rails by 3 to 5 times and even more. The innovative technology proposed has been a result of two decades` research in the field of metal surface hardening achieved by Ukrainian scholars and developers. The technology of metal surface hardening is based on application of electric discharge. Its peculiar features are as follows:
  • the coating to be applied discretely has a mosaic structure;
  • the coating is applied by means of electrodes made of materials that have different physic-mechanical properties;
  • entirety of coating and its depth are determined by operative load and given value of surface friction factor.
  This technology is applied to by joining rail and electrodes to electric circuit and affecting electrodes to move on rotationally along work surface with synchronous input of electric impulses on electrodes.

  The electrodes are fixed on special electrode holder in row one after another. A unit consists of four electrodes which coat 10 mm rail surface in width. The first moves the electrode made of material, exceeding the hardness of rail material. This electrode is forming fragments of layer of plastic deformation resistance with the surface hardness index up to HRñ=60-65. It is followed by two other electrodes and they form fragments of tribotechnical layer. One of electrodes is performed of high viscous material and another - of material with a low surface friction constant. Besides, working surface is covered with layer of alloy additive (graphite).


  1. electrode made of hard material containing ferrous metal
  2. electrode of viscous metal-containing material
  3. electrode of a material with low friction factor containing nonferrous metal
  4. graphite electrode
  5. electrode holder with capability of rotation around the axes
  6. rail surface
  The technological equipment which consists of electric impulse generator, set of electrode holders and electrode cooling device, may be operated as a terminal facility (for implementation on new rails) as well as mounted on a special railway carriage, with the help of which the rails can be processed at the functioning railway track.

  Availability of 9 electrode units allows in one march to apply the coating on the whole working rail head surface at once. Applying speed can be from 1, 5 m/s, with theoretical increase up to the value of 15-17 m/s.

  Power for mobile plant can be supplied from the railways network or the self-contained diesel generator.

  The final technological operation in this technology is an "indentation" of applied discrete sites into surface to be hardened. It is carried out without extra power consumption by means of railway consist passage (during usual exploitation).

  The technology and equipment were successfully tested at one of the major trunk-railways in Ukraine, Kiev-Moscow. There is an appropriate conclusion issued by the Head of Ukrainian Railways. The technology has been approved by European patent # WO 02/101111 of 19.12.2002.

  Application of this technology on the trial railway section in Ukraine resulted in positive effects as follows:
  • rail wear reduced by more than three times as compared with wear of common rails;
  • use of various electrodes enables widely to modify the friction properties of rail working surface;
  • the hardening of working surfaces can be done repeatedly according to their wear.
  The technology is especially effective when applied to curvilinear sections of the railway track.