Noise and vibration

The International Union of Railways (UIC), through its Noise and Vibration Sector (NV), works with its members to better understand noise-generating mechanisms to make tangible progress towards being a better neighbour. The vision of the UIC NV Sector is to provide a global dialogue to integrate sustainability into railway operations and maintenance with a common goal of managing noise emissions better.

There is a growing awareness of the impact of railway noise on public health, which has
resulted in pressure from line-side inhabitants, governments and health organizations for increased noise mitigation. As a consequence, noise can be a limiting factor for many railway operations, introducing additional costs for mitigation, demands for limits on availability/capacity and resistance to expansion of the network.

Recent years have seen the development of new, and refinement of existing, strategies and technologies for noise management. Railway companies often face calls to implement these, and demonstrate that progress has been made with the use of new and innovative technology.

The study reviews noise mitigation measures for rail infrastructure in Europe, focusing on cost efficiency. It compares vehicle-related measures (like brake shoe retrofitting), track-related measures (like rail dampers), propagation path measures (like noise barriers), and receiver measures (like double glazing). The study confirms that rail freight retrofitting is the most cost-effective option, updating previous findings from the STAIRRS project with current data and life cycle cost assessments. Despite challenges in obtaining detailed cost data, the study reaffirms that retrofitting remains the preferred strategy for noise reduction.

The application FreightSimSilent allows all cost-relevant parameters for retrofitting to K or LL brake blocks to be easily manipulated and displayed in diagrams spanning 20 years. This helps users make sound decisions and optimise different retrofitting conditions. The software was developed for UIC by Deutsche Bahn and the IT company join and share.
FreightSimSilent is available in four languages: English, French, German and a user-definable language.

The report explores various noise mitigation options for railways, highlighting both widely used methods like noise barriers and more controversial ones such as rail dampers, acoustic rail grinding, and low-height noise barriers. Due to limited testing opportunities, the UIC Network Noise collected data and experiences from different countries on these measures. The report details the basics of noise control, explains the controversial methods, and summarizes the collected experiences and feedback from UIC members and other European representatives. The information was gathered through requests sent in 2011 and 2012, with additional results from other sources.

When people are exposed to environmental noise, a range of adverse effects may occur. In case of excessive or incidental noise, people tend to complain. In daily life, people can be disturbed in their activities, such as working, communicating or sleeping. In the long turn, these effects may cause annoyance. Annoyance could affect health, because it may lead to irregular hormone secretion, stress, high blood pressure and cardiovascular problems.

Excessive noise during the night may disturb healthy sleep patterns and could lead to awakenings.

For further information about UIC’s publications on the implementation of noise related track access charges (NDTAC), please consult: https://uic.org/sustainable-development/noise-and-vibration/noise-differentiated-track-access-charges

Executive summary
The EU supports railways, because they are the most sustainable means of transportation.
This, however, requires the railways to reduce noise, their most important environmental issue. Noise concern in the EU has led to the Environmental Noise Directive (END), which requires noise maps and actions plans for major railways as well as inside agglomerations. Railway noise emissions of new and upgraded vehicles have recently been limited by EU legislation...

Curve squeal noise, 2005
Curve squeal is an intense tonal noise that may occur on curves or on switches. The high noise level causes annoyance for people living in the vicinity of a squealing railway track as well as for passengers waiting in stations with curves. The character of the noise is very intense with high frequencies (up to 10,000 Hz) and high amplitudes that can be up to 100 dB(A) in 10 m distance.

To answer to this problem, the UIC Combating Curve Squeal project was designed to find measures against the annoying high-pitched noise created during pass-bys of trains in certain curves. A first phase, completed in 2003, was aimed at analyzing existing knowledge and developing models while the second phase, described in the report below, intended to increase confidence in selected mitigation measures.
A selection of friction modifiers and water were tested on two different rigs and under field conditions in Switzerland, France and the UK.
In conclusion, no optimal solutions could be found that would work under all circumstances. For each curve the trade-off between performance, dosage and costs must therefore be evaluated separately.

This report investigates the status and options for retrofitting of the existing European rail freight fleet based on a study commissioned by the European Commission and jointly funded together with the railways (UIC and CER), the wagon owners (UIP and UIRR) and the manufacturers (UNIFE). AEA Technology has been commissioned as consultant, including the specific task of performing an independent third party assessment of the existing activities and results of the rail sector in the field of noise.

This paper contains greater detail of the technical background to the UIC report “Noise Creation Limits for Railways: Main Report on the Railway’s Position”. This technical knowledge has been built up by the collective endeavour of acoustic experts from railways, universities and research institutes over a period of more than 30 years.

Introduction
The UIC (International Union of Railways) has co-ordinated the activity of railways since 1922.
All the principal operating and infrastructure companies are members. For a number of years it has worked to co-ordinate its members’ efforts to minimise the impact of railway activities upon the environment. Among these impacts, the noise created by railway operations is of particular concern. Consequently UIC has played a central role over the past 30 years in co-ordinating the research activities of its members in the area of railway acoustics. This research work forms the foundations for this report, which sets out current knowledge of the phenomenon of railway noise and the potential of technical measures to mitigate it. The report also contains proposals for future achievable and affordable noise creation limits which are based on this knowledge.

Railway Noise Research - Summary of Activities since 1990 - 1998
This report describes the noise research carried out by ERRI and several European railways until 1998. It evaluates the options available to aim for a target of a 20 dB(A) noise reduction for freight vehicles compared with current levels in 1998. The paper concentrates on work that has, in the main, been funded by the UIC but also identifies certain national initiatives.
The summary indicates that a great deal of work has been carried out and a high level of knowledge has been accumulated to find effective solutions to reduce railway noise in its creation and reception.
There are still areas of research where work can be identified to further reduce railway noise but these need to be prioritized to meet strategic aims. However, social and legislative pressures will continue to determine that railways will need to concentrate further efforts on noise reduction techniques.