Many CATs are used to provide the measurements that show where reprofiling work should be undertaken or prioritised. There is considerable overlap between this use and that of CATs for quality assurance: these are both part of the reprofiling process.
Two elements of the CAT software are particularly useful when corrugation surveys are undertaken:
Both a graph and a table are produced to show areas where grinding is required i.e. where the amplitude of corrugation exceeds a pre-defined limit.
An optional extra is so-called “concatenation” software. This software allows several short records to be joined together to produce a single long record. It also provides a method of correcting mistakes e.g. input of an incorrect starting distance and incorrect measuring direction (distance increasing rather than decreasing or vice versa). We would indeed recommend that if a survey is undertaken, measurements are recorded for several short sections of no more than a few km and “concatenated”.
Analysis of more than 9km of CAT measurements on both rails, showing areas where grinding is required as both a graph (left) and a table (right). According to the criteria used, 1.7km of the 9.42km of track (18%) of the track should be reprofiled. These two long records were produced from several shorter measurements that were recorded over several shifts.