Metropolitan Regional Express Services (SERM)
We are supporting the development of these low-carbon multimodal service projects. Built around a railway infrastructure, they promise to improve mobility between cities and their suburbs.
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Rural mobility stations: to promote shared options in rural areas (2:08)
Multimodal public transport services
A tool for the ecological transition...
The aim of these intermodal services is to develop low-carbon everyday mobility, at a time when the transport sector accounts for 31% of greenhouse gas emissions in France. Half of these emissions (51%)1 are due to people travelling by private car, particularly in the suburbs. Aimed at residents of major metropolitan areas and their suburbs, SERMs offer an alternative to car use and are based around one main mode of transport: the train.
...And to break down territorial and social barriers
By better connecting activity hubs close to the urban area with each other, but also with suburban and rural areas, and by helping to develop and revitalise neglected areas, SERMs also work to break down territorial and social barriers.
SERMs in fact play a structuring role in rebalancing the region. By providing a more attractive transport offer, they improve the accessibility of the various areas of the city and thus reduce imbalances between centre and suburbs or between suburbs. They offer sustainable mobility solutions as an alternative to the private car for everyday journeys.
26 projects
of SERMs have been approvedby the State in July 2025
€900M
has been invested by the State in the 2023-2027 CPER2
62,8%
of short-distance journeys are made by car3
A railway backbone
At the heart of these new services, the development of regional trains plays a central role and aims to offer:
- extended timetables
- guaranteed all-day service with clear, regular timetables
- increased frequency at peak times
- an attractive level of service at weekends
- frequent stops in the busiest areas
To make it easier to get to and from the train, SERMs aim for coordinated timetables between the different modes, as well as multimodal ticketing and information.
26 approved SERM projects
The law on SERM4 of 27 December 2023 accelerates and structures their deployment. To date, the government has approved 26 SERM projects. Our companies SNCF Réseau and SNCF Gares & Connexions, the infrastructure managers, are supporting French regions and cities in rolling out these projects in conjunction with the other stakeholders (transport operators, Société des Grands Projets and more). Some SERMs are in the early development stage, while others are more advanced and already operating in initial phases. Examples include Bordeaux, Strasbourg and along the Léman Express.
Harnessing our expertise to deliver SERMs
Teams from SNCF Gares & Connexions and SNCF Réseau work closely with the Société des Grands Projets, local authorities, and regional steering bodies to bring SERMs (Metropolitan Regional Express Services) to life. Our companies leverage their unique and proven expertise in express transport, delivering efficient, reliable services in both urban and suburban areas.