Abstract:
Continuous welded rail (CWR) is a fundamental component of any modern track structure and has several advantages
over former types of rail joining processes. The reduction in maintenance and related costs has become the most
attractive property of CWR although careful monitoring and maintenance of CWR is essential to ensure safe train
operations. Management of the stress-free temperature (SFT) of any section of CWR in order to prevent rail breaks and
lateral buckling that could lead to derailments is a vital duty of the track maintenance team. Variations in the SFT are
influenced by a number of external factors. This paper describes experimental field and laboratory tests carried out to
investigate to what extent the fastening strength influences the variation in SFT in CWR track on Fist fastenings and two
types of pads. The research established a nonlinear relationship between clamping force and rail movement through the
fasteners as well as a strongly linear relationship between clamping force and the variation in SFT. It is also demonstrated
that although the friction coefficient of the pad has an influence on rail movement through the fastener, the primary
factor influencing SFT variations is the clip force. This paper concludes by quantifying the relationship between clamping
force and the expected variation in SFT with clear guidelines on the management of the SFT in CWR.
