Key Findings

• The FEM simulations and previously performed RCFS tests have shown that the ridge present at the intersection of grinding facets on as-ground rail deform and wear quickly.
• Results to date indicate the ridges are not expected to contribute significantly to RCF formation.
• The FEM showed the plastic deformation of the grinding facet ridge on top of the rail did not progress after four load cycles for both the 3.5- and 6.5-degree ridge angles.
• Modelling indicated roughly a 7.1 percent change for the 6.5-degree ridge angle and a 0.75 percent change for a 3.5-degree ridge angle due to plastic deformation.
• The contact stresses were reduced with the increase in contact area in the FEM after plastic deformation but remained higher than the nominal contact stresses without a ridge present. Similarly, in the RCFS tests, the widening of the contact band was noticed over approximately 140,000 cycles after a 2-degree ridge wore off.
• The concentration of the contact stresses caused by the presence of a ridge will cause the wear to be concentrated and occur at a higher rate than what would occur under nominal contact conditions.