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Preventative Rail Grinding

High Speed Grinding (HSG) is a new and unique grinding technology based on very high working speeds of more than 80 km/h. This allows rails to be ground without the need for possession time and/or track closures. The main application area is preventative grinding to avoid rolling contact fatigue and corrugation.

Further information

Rail Care Within Scheduled Traffic
High Speed Grinding is a world first in rail grinding. It is the only method that enables working speeds of 80 km/h and above. The high working speed and low operating costs for network operators make HSG well suited to many different applications.

Areas of Application for HSG:
  • Preventative grinding
  • Acoustic grinding
  • Initial grinding of new rails (removal of the rolling scale)
  • Low friction coating removal

Preventative Grinding
High Speed Grinding combines the best in periodic preventative rail care with a traffic–friendly operating speed.

Preventative grinding with HSG allows:
  • Prevention of rolling contact fatigue (RCF)
  • Improved infrastructure availability
  • Consistent improvement of the rail’s longitudinal profile
  • Significant saving potentials due to rail lifespan extensions and deployment within scheduled traffic

Initial Grinding of New Rails (Removing the Rolling Scale)
The reason for removing the rolling scale through initial grinding is to delay the formation of corrugation and to eliminate rail defects caused during track construction works. According to different customer requirements, anything from 0.2 mm to 0.3 mm of material is removed from the rail surface.

Initial grinding with HSG involves:
  • 5-6 grinding passes causing very little construction interference
  • No removal of any track components
  • Time savings in comparison to conventional grinding machines
  • Money savings in comparison to conventional grinding machines

Acoustic Grinding
Acoustic grinding keeps the rail surface smooth and reduces corrugation.

Acoustic grinding with HSG means:
  • Reduced noise levels through periodic rail care
  • Minimisation of corrugation and slip waves
  • Cost effective, traffic friendly and environmentally friendly

Low Friction Coating Removal
Low friction coatings, primarily in autumn, often lead to considerable traffic disturbances. Also other lubricating films, for example resulting from the pollution from industrial areas close to the tracks, may lead to traction and breaking problems and interferences in signalling.

Removing the low friction coating with HSG enables:
  • Traffic friendly scheduling of the grinding operations
  • Long-term reductions in coating thickness
  • Cost advantages
  • Minimized environmental impact

Basics of High Speed Grinding
High Speed Grinding is based on the concept of circumferential grinding. All grinding stones are passively propelled and hydraulically pressed onto the rail. The patented technology allows working speeds of up to 100 km/h. The material removal of 0.1 mm is normally achieved by three grinding passes (two rough passes and one smoothing pass).

HSG Specifications
  • Material removal rate: approximately 50 µm per grinding pass
  • Working speed: 60 km/h to 100 km/h
  • Switches are passed at working speed but are not ground
  • No signal devices or other track components have to be dismantled

Grinding Results
  • Roughness: Ra: ≤ 8 µm
  • Improvement of rail surface levelness
  • Conservation of rail cross profile
  • Systematic removal of fatigued rail surface layer
  • All process parameters are recorded constantly in order to document the results of the grinding operation