Transilien (tʁɑ̃siljɛ̃) is the brand name given to the commuter rail network serving Île-de-France, the region surrounding and including the city of Paris. The network consists of eight lines: H, J, K, L, N, P, R, and U, each operated by SNCF, the state-owned French railway company. The lines begin and end in major Parisian stations, but unlike the RER network, the Transilien trains do not cross through the Paris city centre. The Transilien brand was established on 20 September 1999 as a way to unify the suburban network that existed since the late nineteenth century. The name "Transilien" is a derivative of Francilien, the demonym for people living in Île-de-France. As part of the rebranding effort, stations and rolling stock were modernized. The area covered does not correspond exactly with the boundaries of the Île-de-France region, with some lines crossing into other regions. On the other hand, some stations located at the margins of the Île-de-France region, are not served by Transilien routes, but instead TER trains from neighboring regions. Transilien trains operate over tracks owned by SNCF Réseau (formerly RFF) and the same tracks are used by mainline passenger trains (TGV and Intercités), by other transport operators (Renfe, Deutsche Bahn, Eurostar, Thalys, and Venice-Simplon Orient Express) and by freight trains. Although not strictly part of the network, the Transilien brand can also be seen on the RER C, D and E lines and tramway lines 4 and 11, which are operated by the same division of SNCF. The first line in the suburbs of Paris opened on August 26, 1837, between Paris' (Saint-Lazare station) and Saint-Germain (the line stops temporarily at Le Pecq). This line was handed over to the RATP on 1 October 1972, when RER A was commissioned. Its immediate success led to the creation of numerous lines, primarily intended to link the main cities of France. Suburban service has long been marginal for large companies, with the exception of the West, where several short lines crossing residential areas are seeing their local traffic increase sharply.
Emmanuel Pierre Jean Ravalet, Marc Antoine Messer