Sanded Wheel–Rail Contacts: Experiments on Sand Crushing Behaviour

Bettina Suhr*, William Skipper, Roger Lewis, Klaus Six

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


In railway operation, the sanding process is used to overcome low adhesion conditions in the wheel–rail contact. In the literature, previously conducted research has been experimental, e.g., measuring adhesion coefficients (ACs) under different contact conditions (dry, wet, . . . ) or applying different sands. Under dry conditions, sanding can reduce measured ACs, while under
wet conditions different types of rail sand can leave ACs unchanged or increase adhesion. Despite active research, the physical mechanisms causing the change in ACs under sanded conditions are still poorly understood. A possible remedy is the development of advanced models of sanding including local effects. As a basis for such a model, this study presents experimental results concerning single grain crushing behaviour of two types of rail sand under dry and wet contact conditions. Firstly, initial breakage behaviour is investigated with focus on the particle fragments’ size and spread as only fragments within the running band are available to influence the AC during roll-over. Secondly,
single grain crushing tests are conducted under realistic wheel–rail load showing the formation of solidified clusters of sand fragments, as well as their size and thickness. This information is important for understanding mechanisms and for future physics-based modelling of the sanding process in wheel–rail contacts.
Original languageEnglish
Article number38
Issue number2
Publication statusPublished - Feb 2023


  • low adhesion
  • sanding
  • single grain crushing tests
  • wheel–rail contact

ASJC Scopus subject areas

  • Mechanical Engineering
  • Surfaces, Coatings and Films

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