Rail grade dependent damage behaviour - Characteristics and damage formation hypothesis

This paper investigates the damage behaviour of several pearlitic rail steels with special focus on three specific damage mechanisms - wear, plastic flow and rolling contact fatigue (RCF, head checks in particular). Multiple tests were conducted on a full scale test-rig at voestalpine Schienen GmbH under dry contact conditions. The obtained results were compared with data from selected track tests. The test-rig is capable of producing realistic contact conditions that allow the formation of wear and RCF defects in very short time periods within 100,000 wheel passes. The test-rig results showed the improved wear and RCF resistance of high strength steels clearly. Additionally, a system wear analysis was conducted to outline the interaction of these high strength rail steels with a standard wheel steel. Although the trends are consistent on the rig and in track, the absolute values concerning wear and RCF differ due to some specific differences between track and test-rig conditions. Finally ideas are postulated that explain on one hand the test-rig specific wear behaviour of the rail grades and on the other hand the formation of periodic, rail grade dependent crack spacing of the defect type head checks.