Rail flatness measurement method based on virtual rules

This paper deals with the problem of measuring the flatness of rails in the final stage of their manufacturing. The flatness must be measured repeatedly along the total length of the rails. Controlling the flatness of manufactured rails is very important: only rails with very good flatness can be used in high speed railways. Rails with moderate flatness defects can be used in standard railways, but if the flatness defects are greater than specific tolerances, the rails must overcome a straightening process or be discarded. To measure flatness, we propose a method based on emulation of the manual measurement process: the placement of virtual rules along the entire length of rails. The goal of using virtual rules is to make the method able to measure the potential rail defects. The results indicate which of the rails meets the minimum quality conditions required and which need to be re-manufactured or even discarded. The proposed method is based on an official standard: the European Standard EN-13674-1-2011. An extensive data-set of rails has been measured to test the performance of the proposed method. Results indicate the proposed method is robust and accurate.