Transilien

Transilien is the brand used by SNCF for the suburban rail services that operate in the Île-de-France region around Paris. The network covers commuter lines that extend from central Paris to the surrounding suburbs and towns, providing frequent urban-to-suburban rail connections and forming a key component of the Île-de-France public transport system. Transilien services are operated by SNCF Mobilités under a contract with Île-de-France Mobilités (IDFM), the regional transport authority responsible for planning and funding regional transit. The network is separate from the Paris RER system, though it integrates with it and with other transit modes such as the Métro, trams, and buses. Fares and passes are coordinated through IDFM, with Navigo passes and other tickets valid across the Transilien network.

The fleet comprises electric multiple units and other rolling stock used for commuter services. In recent years, the network has undergone modernization to increase capacity, improve reliability and reduce travel times, including the introduction of newer rolling stock and upgrading signaling on several lines.

Transilien services have a long history as part of the SNCF regional network serving Île-de-France. The brand was established to distinguish suburban services from long-distance and high-speed trains, and it continues to evolve under regional planning efforts aimed at improving mass transit access for the Paris metropolitan area.