1.1 OverviewThe RailMeasurement (RM

1.1 OverviewThe RailMeasurement (RML) Corrugation Analysis Trolley (CAT) system is a combination of PC software and data acquisition hardware. The CAT is based on a design of hardware that was built at Cambridge University Engineering Department in the 1970s. The complete system has been designed for the in-situ measurement and analysis of longitudinal irregularities: rail corrugation and acoustic roughness.The hand operated trolley contains two active elements: A transducer that runs along the rail, to measure the corrugation; and A counter that emits pulses at regular intervals as the trolley is moved, so that the position of the trolley can be determined.The trolley incorporates signal conditioning of the transducer signal. A combination of electronics and software gives a signal proportional to the position of the accelerometer (and hence the displacement of the rail surface). The trolley counter is used to facilitate recording of the position at 1mm or 2mm intervals (user selectable) along the track.Post-processing software built into the CAT system allows the post-run inspection of the rail displacement, and the analysis of the displacement into several fixed wavelength ranges or one user-defined wavelength range (Section 6.4).Analysis of the raw or filtered displacement can also be performed to generate the following statistics (Section 6.4.1): Moving Average Peak-to-Peak displacement Moving Average Root Mean Square (RMS) displacement Block Average RMS displacementEach statistic-wavelength range combination can have a different averaging window.The raw data, or a section of raw data, can also be processed to provide a third octave analysis (by wavelength) of RMS displacement (Section 6.7)Spike removal algorithms allow data analysis to be performed to the standard prescribed in section 7 of EN15610:2009 (Section 6.4.3).