Several RCAs are used primarily for corrugation surveys, to show where reprofiling work should be undertaken or prioritised on a railway system. Although an RCA on a reprofiling train could be used for this purpose, it would be a poor use of the reprofiling train.
The RCA software produces the same type of “grinding report” as a CAT or bi-CAT, with the critical difference that measurements with the RCA would typically be undertaken at 15km/h or more over both rails whereas the CAT and bi-CAT are restricted to walking speed.
Analysis of RCA measurements between two stations on a metro system taken almost a year apart, where grinding was undertaken after the earlier measurements. The “block-average RMS” is shown in blocks of 50m length, which is a very useful statistic for giving an objective measurement of where reprofiling is required. Based on corrugation in the 30-100mm wavelength range (above) the entire length between stations should be reprofiled, whereas based on the 100-300mm wavelength range (below) about 30% of the distance requires reprofiling. Note how repeatably the corrugation re-establishes itself.