Optical profilometers for rail track diagnostics

Aspects of the optical profilometers usage for control of the rail head internal surfaces and track diagnostics when used as part of a compact track monitoring system (CTMS) are considered. To determine a wide range of track geometric parameters, a position of the `wheel/rail' contact point in each cross section of track is required. Coordinates of the required point may be defined by both contact and optical methods. The latter requires an identification of the rail head profile in scanner data and comparing it with analytical profile. Actual track diagnostics systems determine rail alignment by simultaneous measuring rail position in three sections. This method is only feasible for specialized measuring carriage. However, current trend in the field of rail diagnostics is the tendency to use compact multi-purpose systems able to be installed on any track machine. Using CTMS, implying instrumentation location in a single section, demands special constructional and algorithmic solutions for alignment determining.