A “smart systems” approach for better managing CWR thermal forces at extreme temperatures

The effective management of longitudinal forces in continuous welded rail (CWR) is essential for safe and efficient railroad operations. Compressive forces can cause the track to buckle while tensile forces accelerate rail defect growth and rail/weld/joint failures. The magnitude of these thermal forces is governed by the railrs stress free temperature (SFT). Track maintenance policies require that CWR be installed and maintained within an SFT range to minimize the development of damaging forces. A key impediment to knowing these potentially damaging longitudinal forces is a lack of adequate measurement capability, which has eluded researchers for the past three decades. To fulfil this need, recent technical developments have resulted in improved measurement capabilities for the determination of rail longitudinal force and SFT. One such new measurement capability is based on a rail mounted system referred to as the Rail Stress Monitor (RSM), which is coupled with a sophisticated database management system and applications provider. Together, the technology offers a lsmart-systemr approach to mitigating potentially damaging force levels by providing real time data on CWR longitudinal force/neutral temperature behaviour. This paper provides the fundamentals of the longitudinal force problem, offers a description of the measurement technology, and describes several applications of the technology aimed at more effectively managing CWR longitudinal forces for improved network safety and capacity. Of particular interest is the systemrs application to cold temperature rail break detection and repair, and to hot weather lbuckling hazardr detection and warning.