Author(s): Letourneaux Fabien, Fodiman Pascal, Trolle Benoît, Oger Pascal
The rail roughness plays a key role in the rolling noise generated by trains when passing by. The rail head surface is evolving along time with traffic and also when rail maintenance is performed. In most countries, the rail is regularly reprofiled to remove surface defects (head checks, cracks, ballast prints, …) and/or to ensure a safe dynamic behaviour of rolling stocks. In France this is performed through a dedicated rail grinding policy (mainly preventive-based). In particular, the impact of this grinding process on the short (a few days) and middle (a few years) term has been assessed during a 4 years' project. The analysis of the extensive dataset of different sites showed that the commercial traffic has a rather smoothing effect. On the contrary, just after grinding, an initial degradation of the rail surface is observed, in terms of the overall roughness level as well as in terms of the creation of specific spectral components (deep grooves). This degradation may last a couple of weeks up to months depending on the traffic. This work has led to the definition of specific indicators and associated requirements related to noise. These have been set in an industrial specification sheet for the grinding process, following a feasibility study phase involving industrial partners. The present paper first summarizes the main results of the project. Then it details the two-levels acoustic requirements to be complied with and the corresponding acceptance procedure. The implementation strategy adopted in France in 2017 following the new rail reprofiling contract is also described. Last, first experiences gathered so far are presented together with a provisional feedback on the application of such a process.
Name: Dr Fabien LETOURNEAUX