MAPS-SFT, a new tool in the infrastructure manager’s toolbox

This paper describes a new approach to the integrity management of rail infrastructure using a novel stress management technology - MAPS^{TM a}. The MAPS technology is an approach that offers, for the first time, a portable method for the accurate, non-destructive measurement of stress, a key parameter governing the design, performance and life of virtually all engineering structures. It is a magnetic technique so it can be applied to all materials that display some ferromagnetic behaviour including ferritic steels, cast iron, some stainless steels and some nickel super alloys. MAPS-SFT is a particular embodiment of the technology for the non destructive measurement of the stress free temperature (SFT) of continuously welded rail. The paper explains the technology that is MAPS, focussing on its relevance to rail steels, discusses a specific case study, and goes on to describe the specification of a tool to be used on the UK rail network set by Network Rail, the UK rail infrastructure manager. Some of the challenges in meeting that specification are described and, finally, a brief description of the tool itself is given.