Improvement of the noise Technical Specifications for Interoperability: The input of the NOEMIE project

The Technical Specifications for Interoperability (TSI) are the technical application documents of both European Directives 96/48/EC (high-speed, HS) and 2001/16/EC (conventional rail, CR). In that respect, noise emission levels of the railway system are considered to be a basic parameter for the acceptance of the rolling stock subsystem.The rolling noise, caused by the combination of wheel and rail roughness, is considered to be the main noise generation mechanism involved at both conventional and high speeds. Moreover, the track influence is such that the noise emission limit values cannot easily be set up without a tight definition of a reference track, allowing the noise values to be consistent and reproducible on several test sites. Such track conditions imposed by acceptance tests for rolling stock interoperability are described.In that respect, the NOise Emission Measurements for high speed Interoperability in Europe (NOEMIE) test campaign was launched to provide trackside noise emission values of several high-speed trains at speeds up to 320 km/h. Several existing tracks were realised therefore in five European countries and compared with the reference-track definitions.A new measurement method, based on rail roughness and track vibration response has been developed, leading to an improved common reference-track definition, called TSI+, for both the HS and CR TSI.