Advanced rail materials for maximizing rail life - Development, application, and maintenance practices
Since the early days of railway operation, rail degradation has been a major concern for railway operators. At first the main focus was on wear resistance and general fatigue resistance of rails but this later changed to increasing also the resistance of rails against rolling contact fatigue (crack initiation and growth).
Changes in steel manufacturing technologies like the oxygen blowing process, vacuum degassing and continuous casting significantly contributed to making rails more resistance to damage. Furthermore, also metallurgical improvements (optimizing alloying elements) and advanced rail production technologies (universal rolling technology, roller straightening, heat treatment processes) lead to nowadays used rail grades with fully pearlitic and refined pearlitic microstructure, with hardness levels between 260BHN up to 420BHN, material strengths up to 1400 MPa and sufficient toughness properties while considering other factors like weldability, conductivity, thermal expansion and general maintainability.
On top of this the railway operator nowadays have several tools available to extend the life of rails (besides using rails with optimized material structure) like rail grinding, optimized wheel/rail profiles or friction management.
This paper will discuss the last 50-80 years of rail production, development and application practices as well as will give an outlook on future developments to highlight the importance of this central component of the railway track - the rail.