Modeling has several benefits. It reduces the amount of data needed to describe a rail profile. By giving structure to the data, it enables measurements to be made more quickly. Converting the data to a standard model also makes it possible to perform meaningful comparisons against previous measured or unworn rail profiles. Modeling places profiles in a rail-centered space where the co-ordinate system is anchored to the base and center-line of the rail. This provides a standard frame of reference in which profiles can be compared and measurements derived.