ABSTRACT
This chapter provides a brief overview of the principles of gauging used to test compatibility between trains and structures on railway networks. Building on the principles for determining the dynamic movements of rail vehicles as they travel along the track, the means by which the railway infrastructure measurements are taken and compared with the dynamic swept envelope of the vehicle are discussed, together with concepts of clearance. Principles cover gauging methodologies from static gauging through to (dynamic) absolute gauging, including UIC Reference Profile gauging used on High-Speed Routes in the UK. The chapter considers both conventional and tilting trains and the determination of critical analysis cases from a clearance perspective. It explores how the swept envelope relates to operational parameters such as track geometry, speed and loading conditions. Both classic and probability (risk)-based clearance calculations are discussed, which consider lifetime system tolerances and allowances.
