Noise, like air quality, is a public health issue. According to Ademe, France’s Environment and Energy Management Agency, the social cost of noise pollution is estimated at €147 billion a year. Nearly two-thirds of this is directly linked to the transport sector. Road transport accounts for more than half of the total, while rail represents just under 8% (€11.2 billion).

SNCF Group knows that increasing the modal share of rail for passenger and freight transport requires public trust and support—and that means controlling railway noise. To meet this challenge, our teams have developed a store of technical expertise and foster collaboration among all stakeholders.

Railway noise comes from a variety of sources, including train traffic, station announcements, industrial activities and worksites. For example, a TGV power car idling at a platform produces 92 to 95 decibels (dB), roughly equivalent to a symphony orchestra. From one metre away, unloading ballast can be as loud as standing close to speakers at a concert or dance club (98 to 115 dB). Inside the cab of a mainline locomotive, noise levels range from 78 to 87 dB, somewhere between the sound of a barking dog and a kitchen mixer. But decibel levels alone don’t tell the whole story. Perceived discomfort varies depending on individual sensitivity, time of day, sleep patterns, and other factors.

European rail companies must comply with technical specifications for interoperability (TSIs) related to noise, which set limits on rolling stock sound emissions. Within SNCF Group, SNCF Réseau is responsible for managing noise impacts on people who live and work near railway lines, while teams operating in buildings such as stations and industrial sites are accountable for the noise they generate.

For over 20 years, SNCF Réseau’s teams have been working to reduce railway noise and limit its impact on people living near our facilities. We comply with all applicable regulations, which vary depending on the type of noise involved:

• Traffic noise—average noise level limits are set for daytime (6am to 10pm) and nighttime (10pm to 6am)
• Operational and neighbourhood noise
• Worksite noise

In line with regulatory requirements, we take a range of preventive measures to limit noise along railway lines:

• Rail projects are eco-designed to ensure compliance with noise limits that protect local residents
• Tracks are classified by noise level, so property developers can identify the acoustic barriers required whenbuilding alongside rail lines

To protect residents in areas built before noise regulations were introduced, SNCF Group also carries out targeted mitigation work to help reconcile the growing demand for rail transport with urban development. In these “rail noise blackspots”, sound abatement efforts focus on soundproofing panels and insulation for existing buildings. 
Mitigation efforts target:

• Sensitive buildings such as schools, community facilities, healthcare centres and homes
• Buildings exposed to noise levels of 73 dB or more during the day or 68 dB or more at night
• Structures built before 1978, when track noise classification was introduced

Other noise-reduction measures include:

• Replacing short rails with long welded rails
• Replacing wooden sleepers with concrete sleepers
• Installing track dampers 
• Using sound barriers or acoustic screens

Technical specifications set train-specific noise limits for parking, acceleration, operation and braking. Rolling noise mainly comes from onboard components such as motors and fans, wheel-rail contact at speeds over 50 km/h, and wind noise at very high speeds.

Noise can be significantly reduced by limiting parking and component noise, replacing cast-iron brake shoes with composite materials, and improving train aerodynamics and rolling stock design.

Public address announcements are essential to keep passengers informed, but we work to ensure messages are clearly audible without causing unnecessary disturbance to nearby residents and workers.

Sound systems are designed accordingly, with careful attention to speaker placement, and different volume levels for daytime and nighttime use. Human-presence detection systems also help avoid announcements on empty platforms.

We further improve our stations’ acoustic comfort by creating quiet spaces in waiting areas, away from the loudest parts of stations. When designing stations, sound is fully integrated into the process through assessments, acoustic modelling and technical studies.