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| | Product Features
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.
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