All our rail corrugation measuring products use proprietary application software that has been developed in close collaboration with our clients to give output appropriate to their various requirements. The software is updated frequently with new features.
Both the CAT and the RCA store raw profile data from which measurement statistics are derived. The CAT stores rail profile data at intervals of 1mm or 2mm (selectable), and with a precision of 0.01 micron. The RCA stores rail profile data at intervals of 2mm and with a precision of 1 micron. Because the typical lengths of rail measured by the HSRCA are much greater than those of the CAT or RCA, the HSRCA does not store the raw rail profile data, only the measurement statistics derived in real time from this data. For specialised presentation or data processing, all applications can export measured or derived data in a standard plain text form suitable for processing by other applications.
The severity of corrugation can be assessed objectively using the so-called percentage exceedence. This principle is currently embodied in a draft European Standard for rail grinding and reprofiling, prEN 13231-3. Calculation of percentage exceedences is included in software for all three measuring systems.
One of the simplest forms of output from the CAT software is illustrated in the upper figure here, which also illustrates the accuracy of the instrument: the figure shows a comparison between filtered profiles of a 0.9m long reference beam measured with the CAT and with a Coordinate Measuring Machine (CMM). We are not aware of any other equipment for which similar comparisons have been made in order to assess accuracy rather than simply repeatability.
As the calibration of the CAT can be independently checked, it can be used as a reference instrument to verify the performance of the RCA and HSRCA. An example of the type of comparison that can be made directly in the CAT software is illustrated in the lower figure. In this example, the filtered profile, percentage exceedence and one-third octave spectra are compared for measurements made using the RCA and the CAT over the same 10m length of track. Similar comparisons can be made for lengths of track from fractions of a metre (for the examination of individual irregularities) to kilometres.