CATs are widely used for rail reprofiling work, both to show where reprofiling is required and to demonstrate that this has been undertaken successfully. The instrument is one of the few (if indeed not the only instrument) that can be used routinely and reliably to demonstrate a complete site has been reprofiled to the requirements of EN ISO 3095 or EN 15610. These requirements are substantially identical to those of EN13231-3:2006, which is a more demanding standard than the later EN13231-3:2012. Some of the earliest CATs are still used routinely for this work after giving more than a decade of regular service. Our equipment is both robust and extremely reliable: our clients and those for whom they are working can trust the results that are obtained from it.
The CAT software continues to be developed to give all the results that a user might require and that are contained in the standards and specifications of which we are aware. This includes statistics such as filtered displacements (including all common pre-defined filters and a user-selectable filter that can be used for any other wavelength range), moving averages (both peak-to-peak and RMS), and RMS block average and exceedences.
The CAT can be used for measurements of longitudinal irregularities at all stages of rail reprofiling, from planning of work through to Quality Assurance of the finished rail.
CAT measurements of 370m of the same rail, one night before and one night after grinding. In the 30-100mm wavelength range shown, irregularities have been brought well within those allowed for Class 1 reprofiling in EN13231-3:2012: a level of +/-0.010mm is exceeded over 0% of the grinding site. The one-third octave spectra (lower part of Figure) show that corrugation was severe at about 50mm before grinding, and there is residual corrugation after grinding despite compliance with EN13231-3:2012. The peaks in the spectrum of post-grind irregularities reflect the “grinding signature”.