Railway noise is still the main rail externality and according to the EEA’s Outlook to 2030 report, the number of people who are touched by railway noise is projected to increase under both optimistic and conservative scenarios. This has an impact on the political decisions when upgrading existing or building new railway lines.

During the past years, along with noise, the effects from railway-induced vibrations has come more and more in the focus. In this perspective, the project to be developed under this call shall provide feasible solutions on improvement of prediction tools on vibration impact. It should also provide an assessment method on how vibration emissions can be determined and specified independently of location and track influences in the future to determine the effect of the train alone independent from the track.

A strong cooperation with standardization and regulation committees through the EU-RAIL SP should enable simplified vibration impact assessment as well as N&V certification procedures.

Noise

The main objective of this work area is to improve EU noise mapping and to define relevant limit values that could potentially serve as a basis for upcoming revisions of the Technical Specifications for Interoperability on Noise.

The R&I work of this work area should contribute to/is expected to:

• Deliver noise mitigation strategies for reprofiling/grinding processes;
• Facilitate the development and implementation of onboard measurement systems for rail acoustic roughness, by providing a common technical measurements guideline in Europe;
• Deliver a user-friendly tool making use of open-source data to help optimise future re-profiling processes to minimise the noise impact of railways;
• Deliver track LCC analyses based on the knowledge of acoustic and track experts from a holistic approach and deliver a user-friendly tool making use of open-source data to support the minimisation of Noise externalities during LCC analyses. Such analyses should be made publicly available;
• Progress towards virtual and cost-effective vehicle certification considering uncertainties of pass-by noise measurement;
• Improve the prediction of noise in curves for urban and inter-urban railway lines against state of the art.

Ground Vibrations

The main objective of this work area is to improve the prediction tools capabilities for holistic ground vibration impact.

The R&I work of this work area is expected to provide tools:

• with simulation capabilities for ground vibration;
• for large scale environmental impact studies, making use as much as possible of existing soil databases and Geographic Information System.

Additionally, considering that existing TSIs do not cover vibration emissions from rolling stock, and in general there is no standardised procedure for vibration emissions measurement, the R&I work should deliver:

• A procedure for the track- and site-independent verification of vibration emissions, including an analysis and determination of applicable conditions for its re-use on other sites.
• An assessment method on how ground-borne vibration emission of rolling stock can be determined.

These outputs should serve as an input to the EU-Rail System Pillar for possible consideration on standardisation (EN) and regulation updates (TSI). The work should therefore also include proposals for the definition of suitable, demanding but realistic limit values for the development and acceptance of new ‘low vibration’ rolling stock.

The following R&I areas have been identified within the scope of this topic. It is up to the applicant to identify the most appropriate R&I work-streams, taking into account the state of the art and previous R&I work – in particular in the context of Shift2Rail activities^[1] – for delivering upon all of the above expected outcome.

On-board measurements of the rail acoustic roughness

The research activities around this area should investigate an effective approach for optimised rail reprofiling processes that minimises nuisance to lineside residents and avoid high maintenance costs.

They should look at on-board measurement of rail acoustic roughness aiming at establishing harmonised technical European guidelines.

They should support the development of the necessary tools enabling the introduction of on-board measurement data for acoustic rail roughness, to support the optimisation of future re-profiling process by minimizing the noise impact of railways. The maintainability of the tool shall be addressed.

Rail optimisation for noise, vibrations, and life cycle costs

The research activities around this area should investigate how to integrate noise and vibration abatement methods into asset management plans, considering the impact on environmental and health conditions, to optimise the track system for LCC, noise and vibrations simultaneously.

The research action should deliver the necessary tools supporting the whole system optimisation for noise, vibrations and life cycle costs (LCC) on railway tracks. The maintainability of the tool shall be addressed.

Noise in curves

Rolling noise is in many situations the major railway noise source. However, in urban areas, especially for tramway systems, curve noise is the dominating reason for noise complaints. Furthermore, current standards, e.g. ISO 3095/3381, and regulations, e.g. TSI Noise, only cover rolling noise in straight alignments. In order to improve prediction and to reduce noise, research activities around this area should look into:

• Rolling noise in curves, developing a digital twin-based approach to predict rolling noise for curves with radius R>150 m, validated by on-field measurements.
• Squeal and flange noise, developing an engineering tool for the prediction of critical curve situations and the assessment of the impact of noise mitigation solutions with a focus on urban rail (curve radius < 150 m). The tool shall be validated against on-field measurements.
• Improve the EU-CNOSSOS curve noise factor^[2].

Transposition and uncertainties of pass-by noise

Virtual or simplified acoustic certification of rolling stock needs to consider uncertainties regarding measurements and, therefore, research activities around this area should look into:

• Transposition from one site to another, investigating application and looking for improvement of the methods developed in the S2R funded project TRANSIT ^[3] especially to sites with important differences in the track architecture.
• Assessment of uncertainties in pass-by noise measurements.
• Identification of a methodology to acoustically certify freight wagons without testing - at least for freight wagons without additional noise sources apart from the rolling noise.
• Study of the current noise emissions of new propulsion technologies (Battery propelled rolling stock, hydrogen rolling stock). Propose specific limit values for these propulsion technologies for pass-by, starting and stationary noise, if needed.

Ground vibrations Prediction Tool

The research activities should advance the state of the art, see Silvarstar public deliverables D1.1 , 1.3, 2.1 and D3.2^[4] possibly based on existing prediction tools for ground vibration impact. In particular the following areas are in the scope of interest:

1. Urban railway traffic

Prediction tool for ground vibration impact supporting urban areas (with tramways, metro, and light rail systems) and investigating excitation mechanisms in curves, switches and crossings as well as dedicated urban soil characteristics.

b. Integration into environmental impact assessment tools

Integration in the prediction tool of GIS data concerning track, soil and building data and further automated processing of large-scale projects should be part of the R&I activities. The research activities should consider the application of a user-friendly graphical user interface for the usage of the simulation and prediction tool, preferably with interfaces to commercial geographical information system (GIS) based software for noise and general environmental impact.

The Project stemming from this topic shall also consider the future acceptance and reliability of the developed tool, by addressing aspects such as the assessment of prediction uncertainties and its integration into ground vibration standards. Additionally, the prediction for mitigation measures at track side, suitable for both tunnels and open track lines, and to the integration of mitigation measures in the transmission path (e.g. tranches, walls) and estimation of their insertion loss shall be addressed.

The tool shall provide enough open interfaces to enable the integration of further improvements and developments.

Requirements and specifications for ground-borne vibration emission of rolling stock

The research activities should address this area by investigating:

• Numerical analysis/simulation of the most important parameters in vehicle construction responsible for vibration emissions.
• A suitable descriptor which can describe and compare vibration emissions of trains.
• A procedure to determine the most important parameters of track influences on ground-borne vibration and proposals for a normalized reference track surrounding vibration emission specification.
• An assessment method on how to specify and verify vibration emission of vehicles alone, independently from track influences, including some specifications on how to transfer the data from a test site to a reference track.
• The typical state-of-the-art vibration emission for different train categories including some proposals for limit values.
• A way to determine and compare vibration emission values track and site independently, in support of possible future standardisation activities.

Interactions with other EU-RAIL projects and EU-Missions

The action to be funded under this topic shall:

• Take into account the outputs of linked projects from EU-RAIL Flagship Areas 4^[5] and work together for any potential interfaces.
• Interact with EU-Rail System Pillar^[6] for the aspects related to standards and EU-regulations.

Gender dimension

In this topic the integration of the gender dimension (sex and gender analysis) in research and innovation content is not a mandatory requirement.

[1] SILVARSTAR (http://silvarstar.eu/), FINE-2 (https://projects.shift2rail.org/s2r_ipcc_n.aspx?p=fine-2), TRANSIT (https://transit-prj.eu/home.aspx),

[2] CNOSSOS-EU noise mapping (https://publications.jrc.ec.europa.eu/repository/handle/JRC72550

[3] Please refer to the project’s public deliverables (https://transit-prj.eu/Page.aspx?CAT=DELIVERABLES&IdPage=aeae1af3-e01e-499b-bfab-52b38411eafb) and other publications (https://transit-prj.eu/Page.aspx?CAT=DOCUMENTS&IdPage=ece4856c-d4a8-4ebe-8ece-c77c069f71a2).

[4] https://projects.shift2rail.org/s2r_ipCC_n.aspx?p=S2R_SILVARSTAR

[5] https://projects.rail-research.europa.eu/eurail-fp4/

[6] https://rail-research.europa.eu/system_pillar/