Abstract RCA equipment supplied by RailMeasurement Ltd is used routinely on reprofiling trains to show when irregularities have been brought within limits stated in reprofiling specifications and on other vehicles to help schedule reprofiling. It has been shown previously that these measurements correlate well with those made using the CAT instrument, which is widely used to take measurements of rail irregularities for acoustic purposes. The measurements presented here from routine use of RCA equipment illustrate several interesting features. For example, the distribution of irregularities along the track varies little in time despite the maintenance that would have been undertaken during the almost two year period over which measurements are shown for one line. There is strong evidence that long wave (1–10 m) irregularities are relatively low on non-ballasted trackforms that have been well laid and well maintained, whereas such irregularities are both more variable and generally more severe on ballasted track. Conventional grinding brings about a substantial reduction in irregularities in the 40–1000 mm wavelength range, with a modest reduction at best at longer wavelengths and a substantial increase at shorter wavelengths. The increase arises from the well-known “grinding signature” i.e. the pattern that is imprinted at the wavelength that a grinder moves forward during one rotation of a grindstone. As a result, there is very little ground rail on which irregularities are lower than the EN ISO 3095:2013 limit line for smooth rail for wavelengths of less than 35 mm. A specific reprofiling technique, such as offset or shuffle-block grinding, would be required to reduce irregularities in this wavelength range. Irregularities on metro systems are extremely variable, with little if any consistency between nominally similar trackforms (such as sleepers laid in concrete) on different metros. There is some evidence that the newest metro systems for which data are presented here do have lower long wave irregularities.


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    Titel :

    Routine Measurement of Long Wavelength Irregularities from Vehicle-Based Equipment


    Beteiligte:


    Erscheinungsdatum :

    2018-01-01


    Format / Umfang :

    10 pages





    Medientyp :

    Aufsatz/Kapitel (Buch)


    Format :

    Elektronische Ressource


    Sprache :

    Englisch




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