1 Scope

This document specifies methods for measuring and analysing irregularities of running surfaces for use in the prediction and assessment of ground-borne noise and vibration arising from railway systems. This document

1. defines the data that can be described as rail or wheel roughness and that can be used to quantify a source term for the generation of the dynamic forces that can lead to ground-borne vibration from railway vehicles,

2. gives guidance regarding the types of equipment that can be used to measure roughness as a variation of height along the running direction of the rail surface or wheel parameter,

3. gives guidance regarding the methods that can be used to obtain an estimate of the roughness wavelength spectrum from measurement records taken over a length of rail head or wheel perimeter, and

4. gives guidance regarding the presentation of a roughness spectrum representing the condition of a length of rail or of a wheel related to its ability to generate vibration.

This document does not

5. give guidance regarding the characterization of localized geometrical features (e.g. switches, crossings, rail squats, occasional rail joints and localized geometrical defects of the running surface). These features are likely to produce dynamic forces that are not linear with their amplitude because of the change of geometry at the wheel-rail contact. Hence these features are not characterized by methods of analysis defined within this document. Annex A provides further information regarding the characterization of localized geometrical features,

6. give guidance regarding the specification or testing of roughness measurement equipment that can be used. Annex B provides an overview of measuring equipment,

7. give guidance regarding the measurement or analysis of track quality for any other purpose than the assessment of ground-borne vibration,

8. present any example of roughness spectra intended to represent typical roughness. Roughness levels vary greatly between track sites and any examples used in this document have not been selected on any other basis than their usefulness for the purpose of demonstrating the principles of analysis,

9. promote any particular make, model or manufacturer of measurement equipment, and

10. recommend or promote software for the implementation of the analysis procedure.