Transilien Line U

• 22 July 1988: A proposal is submitted to the Syndicat des transports parisiens for a suburb-to-suburb tangentielle line between Saint-Quentin-en-Yvelines and the business district of La Défense.
• July 1991: The proposal is approved by the Syndicat des transports parisiens, with the line reusing existing infrastructure from the Grande Ceinture line.
• 28 May 1995: The La Défense–Saint-Quentin-en-Yvelines line is opened to the public.
• end of 2004: The line is renamed Line U as part of a reworking of the Transilien network.

On August 2, 1839, the current section linking La Défense to the Viroflay connection was put into service as part of the line from Paris-Saint-Lazare to Versailles-Rive-Droite. The latter is the second created in Île-de-France after the line from Paris-Saint-Lazare to Saint-Germain-en-Laye. It makes it possible to link Paris to Versailles in a shorter time, to bring many visitors to the castle, which is at the end of its restoration, and to bring economic development to the region.

The line is the result of the project of a bridge and road engineer, Desfontaines. He had proposed to join the line of Versailles right bank to that of Saint-Germain, which limited the costly expropriations, and also restricted the ramp to a value of 5 mm / m, at the cost of a slightly longer route.

On July 12, 1849, the section between the Viroflay connection and La Verrière station was opened in turn, as part of the line from Paris-Montparnasse to Brest.

In July 1852, the lines from Paris-Saint-Lazare to Versailles-Rive-Droite and from Paris-Montparnasse to Brest were linked together through the Viroflay connection.

On July 22, 1928, the section going from the current station of La Défense to the Viroflay connection (Line from Paris-Saint-Lazare to Versailles-Rive-Droite) was energized, in direct current 650 V by 3rd rail. This electrification is accompanied by the generalization of high platforms, the replacement of its ancient steam traction equipment, much criticized for its discomfort, by modern “Standard” trains, which remained emblematic of the Saint-Lazare suburb for more than fifty years .

In April 1959, a new stop was created on the line to La Défense. Its objective is to serve the Center for New Industries and Technologies or CNIT, but this stop is then considered temporary and is only open during events. The final station was only opened in 1968 with the aim of serving the business district which has been booming since the early 1960s.

• La Défense
• Puteaux
• Suresnes-Mont-Valérien
• Saint-Cloud
• Sèvres–Ville-d'Avray
• Chaville-Rive-Droite
• Versailles-Chantiers
• Saint-Cyr
• Saint-Quentin-en-Yvelines–Montigny-le-Bretonneux
• Trappes
• La Verrière

Major stations:

• La Défense

The eastern terminus of the line, La Défense station offers a connection with metro line 1, RER A, tram line T2 and line L of the Transilien Paris Saint-Lazare network. In the future, the tangential line U will correspond with the western extension of the RER E (Éole), to Mantes-la-Jolie, from its current terminus of Haussmann - Saint-Lazare. Line E of the RER will pass through La Défense.

• Versailles-Chantiers

At the center of a seven-branch railway star, the station offers a connection with the RER C, the Transilien line N, and the TER Center-Val de Loire and TER Basse-Normandie services. The Main Lines network serves Versailles-Chantiers station with the stopping of some Intercity or TGV trains.

• Saint-Quentin-en-Yvelines–Montigny-le-Bretonneux

This important station, in terms of attendance, is the main station of the agglomeration of Saint-Quentin-en-Yvelines. It connects with line N of the Transilien Paris-Montparnasse network (connecting Paris-Montparnasse to Rambouillet) and is the terminus of one of the western branches of the RER C

Line U is a line operated by the SNCF, from La Défense to La Verrière, which operates from 5 am to midnight, using sixteen Z 8800 trains. These trains use the Viroflay connection which was, at this time. occasion, open to commercial traffic, in order to connect the extreme terminals in 43 minutes. In addition, during the week, the line provides 89 daily departures.

It does not work during the special night service set up on the occasion of important events such as the Music Festival and New Year's Eve, between 1 a.m. and 5 a.m.

A study, published in the newspaper 20 minutes presented this link as the penultimate of Île-de-France in terms of respect for timetables, because it is a transverse link directly influenced by traffic from Montparnasse and Saint-Lazare networks and to be part of saturated traffic between La Défense and Saint-Cloud, and between Versailles-Chantiers and Saint-Quentin-en-Yvelines.

• List of Transilien stations