Improvement of the noise Technical Specifications for Interoperability: The input of the NOEMIE project
Introduction
Railway environmental noise control has recently experienced major developments induced by both technical advances and regulatory demands at European level following ambitious environmental policy goals.
From a technical point of view, the behaviour of the interface between the track and the rolling stock has a major influence on the noise emission value. The main generation mechanism involved at both conventional and high speeds being the rolling noise excitation, is caused by the combination of wheel and rail roughness. The respective noise contribution of both the rolling stock and the track components needs to be established, this latter contribution being considered significant for current commercial speeds up to 300 km/h. Moreover, the track influence is such that the noise emission limit values for vehicles cannot easily be specified without a tight reference-track definition, allowing the emission values to be consistent and reproducible on several test sites.
Section snippets
TSI: the requirements for noise emission
From a noise emission policy approach, the conditions imposed by the interoperability directive for rolling stock acceptance tests—type testing to be performed to get the EC label allowing to put into service on the Trans European Network (TEN)—are described within the railway Technical Specifications for Interoperability (TSI).
The TSI, which all new rolling stock operated on the TEN have to comply with, impose noise emission limits for railway vehicles. Compliance with these noise emission
The main objectives
In the scope of the revision process of the HS-TSI, the NOise Emission Measurements for high speed Interoperability in Europe (NOEMIE project) was launched in order:
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to provide a common database of comparable and reproducible noise emission values of high-speed trains in Europe;
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to contribute to the specification of a reference track to be used in noise emission type testing, which would be part of an operational line rather than a dedicated laboratory test track;
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to propose and validate a common
Check of the reproducibility of the noise emission in the case of two tracks with soft pads
Following phase 1, complementary studies were performed in the scope of the NOEMIE test campaign, in order to assess the influence of pad stiffness on the trackside pass-by noise emission.
In that respect, a regular “soft” padded track section in Solpke (Germany), adjacent to the NOEMIE German “stiff” reference track, was prepared as reference track as well. That is, with the exception of the rail pads both track sections are identical (ballasted track, monobloc sleepers, UIC60 rail, rail
The existing TSI and ATSI limits definition
During the NOEMIE project advantages and drawbacks of both ATSI and TSI parameters could be assessed under comparable test conditions, vs. noise results. In that respect, testing the ATSI track specification showed that
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the initially proposed ATSI rail roughness spectrum amplitude limits were not realistically achievable on operational high-speed lines;
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the TDR criteria could be tightened to create a test, that is less dependant on variations of the track design, and ensuring, that the wheel
Conclusion
In the scope of railway interoperability, the noise emission values of high-speed trains were assessed within the NOEMIE project (phase 1), showing that the present TSI limits are difficult to achieve with existing rolling stock.
In that respect, specific measurement methods were used to assess the track characteristics, in both the HS and CR domains, and proposed as an appendix to the CR TSI document. New improvements were developed therefore, so a common reference-track definition for the
Acknowledgements
The NOEMIE project has received funding from the EC. This paper reflects the opinion of its authors only: therefore, neither the EC nor AEIF are liable for any use of the information contained therein.
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