Editing Réseau Express Régional

{{DISPLAYTITLE:{{lang|fr|Réseau Express Régional|nocat=y}}}}
{{Short description|Railway system in the Paris region}}
{{For|other usages|RER (disambiguation){{!}}RER}}
{{Use dmy dates|date=November 2014}}
{{Infobox public transit
| box_width = 
| name = {{lang|fr|Réseau Express Régional}} (RER)
| native_name = 
| image = Paris transit icons - RER.svg
| imagesize = 75px
| image2 = Z 20900 du RER C - Transilien SNCF.jpg
| imagesize2 = 250px
| caption2 = [[RER C]] train at [[Villeneuve-le-Roi station]]
| owner = [[RATP Group|RATP]] and [[SNCF]]
| locale = [[Île-de-France]], [[Hauts-de-France]] and [[Centre-Val de Loire]]
| transit_type = Hybrid [[commuter rail]] and [[rapid transit]]
| lines = 5
| stations = [[List of RER stations|257]]
| ridership = 
| annual_ridership = 983 million (2019)<ref>{{Cite web |date=October 2023 |title=La qualité de service du réseau express régional (RER) en Île-de-France |trans-title=Île-de-France Regional Express Network (RER) service quality |url=https://medias.vie-publique.fr/data_storage_s3/rapport/pdf/291464.pdf |publisher=[[Cour des comptes (France)|French Court of Accounts]] 'Annexe n° 1 : consistance et caractéristiques du réseau RER'|page=92 |format=PDF}}</ref>
| chief_executive = 
| headquarters = 
| website = 
| began_operation = {{Start date and age|1977|12|09|df=yes}}
| operation_will_start = 
| ended_operation = 
| operator = [[RATP Group|RATP]] (RER A and B)<br>[[SNCF]] (all lines)
| marks = 
| host = 
| vehicles = 
| headway = 
| system_length = {{convert|602|km|mi|abbr=on}}
| notrack = 
| track_gauge = {{RailGauge|sg|allk=on}}
| ogauge = 
| minimum_radius_of_curvature = <!-- {{convert|0|ft|0|in|mm|0}} -->
| el = [[Overhead line]], {{1,500 V DC}} (RATP) or {{25 kV 50 Hz}} (SNCF)
| average_speed = 
| top_speed = {{convert|140|km/h|mph|abbr=on|round=10}}
| map = [[File:Paris RER.svg|300px]]
| map_name = Vector map of the network showing the outline of [[Île-de-France]]
| map_state = collapsed
| alt = 
| caption = 
| area served = 
| line_number = 
| start = 
| end = 
| character = 
}}
The '''{{lang|fr|Réseau Express Régional}}''' ({{IPA|fr|ʁezo ɛkspʁɛs ʁeʒjɔnal}}; {{langx|en|Regional Express Network}}), commonly abbreviated '''RER''' ({{IPA|fr|ɛʁəɛʁ|pron}}), is a hybrid [[commuter rail]] and [[rapid transit]] system, similar to the [[S-Bahn]]s of German-speaking countries and the [[Milan S Lines|S Lines]] of [[Milan]], serving [[Paris]] and its [[Île-de-France|suburbs]]. It acts as a combined city-center underground rail system and suburbs-to-city-center [[commuter rail]]. In the city center, it acts as a faster counterpart of the [[Paris Métro]], having fewer stops.

Conceived of as a {{lang|fr|métropolitain express}} ('express [[rapid transit|metro]]') during the mid-1930s, the scheme was revived in the 1950s and construction began in the early 1960s. The RER was not fully conceptualised until the completion of the {{lang|fr|Schéma directeur d'aménagement et d'urbanisme}} (roughly: 'master plan for urban development') in 1965. The RER network, which initially comprised two lines, was formally inaugurated on 8 December 1977 in a ceremony that was attended by President [[Valéry Giscard d'Estaing]]. A second phase of construction commenced at the end of the 1970s which saw additional lines constructed along with extensions to the original two. The RER is operated partly by [[RATP Group|RATP]], the authority that operates most of the public transport in Paris, and partly by the [[SNCF]], France's national rail operator.

As of 2023, the network consists of five lines: [[RER A|A]], [[RER B|B]], [[RER C|C]], [[RER D|D]] and [[RER E|E]]. The network has 257 stations and has interchanges with the [[Paris Métro|Métro]] and [[Transilien|commuter rail]] within the City of Paris and the suburbs. The lines are identified by letters to avoid confusion with the Métro lines, which are identified by numbers. The network is still expanding: RER E, which opened in 1999, is planned for westward extension toward [[La Défense]] and [[Mantes-la-Jolie]] in two phases by 2024–2026. The performance of the RER has made it a model for proposals to improve transit within other cities.<ref>{{cite web |url = http://www.thetransportpolitic.com/2009/07/16/regional-rail-for-new-york-city-part-i/ |title = Regional Rail for New York City – Part I |publisher = thetransportpolitic.com |date = 16 July 2009}}</ref> In November 2022, French President [[Emmanuel Macron]] announced the creation of additional RERs that will serve the ten largest French metropolises by 2040.<ref>{{cite web |url = https://www.railtech.com/infrastructure/2023/01/20/12-billion-euro-overhaul-of-major-rail-hub-in-france-takes-shape/ |title = 12-billion-euro overhaul of major rail hub in France takes shape |first = Emma |last = Dailey |publisher = railtech.com |date = 20 January 2023}}</ref>

==Characteristics==
The RER contains 257 stations, 33 of which are within the city of Paris, and runs over {{convert|602|km|abbr=on}} of track, including {{convert|81.5|km|abbr=on}} underground. Each line passes through the city almost wholly underground and on tracks dedicated to the RER, but some city center tracks are shared between line D and line B. The RER is operated partly by [[RATP Group|RATP]], the authority that operates most public transport in Paris, and partly by [[SNCF]], the national rail operator.<ref name="Blakely 17">Blakely 1993, p. 17.</ref> The system, which is structured in a traditional radial arrangement, operates a through-service and uses a single fare model that works seamlessly with several other public transit systems.<ref name="Blakely 517">Blakely 1993, pp. 51, 57.</ref> Total traffic on the central sections of lines A and B, operated by RATP, was 452 million people in 2006; in the same year, total traffic on all Paris area commuter lines operated by SNCF (both RER and [[Transilien]] trains) was 657 million.<ref>[http://www.paris.fr/portail/viewmultimediadocument?multimediadocument-id=31277 Les transports en commun] {{Webarchive|url=https://web.archive.org/web/20090105052810/http://www.paris.fr/portail/viewmultimediadocument?multimediadocument-id=31277 |date=5 January 2009 }}, edition 2005-2006, Mairie de Paris.</ref>

RATP manages 65 RER stations, including all stations on [[RER A|Line A]] east of [[Nanterre-Préfecture station|Nanterre-Préfecture]] and those on the branch to [[Saint-Germain-en-Laye]].<ref>{{cite web |url = http://www.ratp.fr/en/ratp/c_5046/rer/ |title = Line A: a priority |publisher = RATP |access-date = 11 November 2011 |url-status = dead |archive-url = https://web.archive.org/web/20111028233945/http://www.ratp.fr/en/ratp/c_5046/rer/ |archive-date = 28 October 2011 |df = dmy-all }}</ref> It also operates stations on Line B south of [[Gare du Nord]].<ref>{{cite web |url = http://www.ratp.fr/en/ratp/c_11200/new-management-system-for-line-b/ |title = New management system for line B |publisher = RATP |access-date = 11 November 2011 |url-status = dead |archive-url = https://web.archive.org/web/20120403015947/http://www.ratp.fr/en/ratp/c_11200/new-management-system-for-line-b/ |archive-date = 3 April 2012 |df = dmy-all }}</ref> Other stations on the two lines and those on lines C, D and E are operated by SNCF. Of the RER stations operated by RATP, 9 have interchanges with Métro lines, and 9 allow transfer to SNCF's Transilien service.<ref>Statistiques Annuelles 2006, Départiment Commercial Tarification, Vente Résultats LAC A73 54,quai de la Rapée-75599 Paris</ref> In comparison to the Metro, the RER provides better coverage of Paris' suburbs and typically operates at higher speeds and with greater distances between stations.<ref>{{cite web |url = https://londonist.com/london/transport/railways-around-the-world-that-inspired-crossrail |title = Railways Around The World That Inspired Crossrail |first = Harry |last = Rosehill |publisher = londonist.com |date = 27 April 2022}}</ref> Within the city center, RER services practice limited stop operations.<ref name="Blakely 11"/>

==History==

===Origins===

Its roots are in the 1936 ''[[Henri Ruhlmann|Ruhlmann]]–[[Marc Langewin|Langewin]]'' plan of the {{lang|fr|[[Compagnie du chemin de fer métropolitain de Paris]]}} (Metropolitan Railway Company of Paris) for a "{{lang|fr|métropolitain express}}" (express [[rapid transit|metro]]). The company's post-war successor, RATP, revived the scheme in the 1950s, and in 1960 an interministerial committee decided to go ahead with the construction of an east–west line.<ref name="official hist"/> Subsequently, the central part of the RER was completed between 1962 and 1977 in a large-scale civil engineering project whose chief supervisor was [[Siavash Teimouri]]. The construction of the RER was a major undertaking, being highly visible to both Parisians and visiting tourists at various sites across the city for an extended period.<ref>Vitry and Sage 2018, pp. 87-88.</ref>

As its instigator, RATP was granted authority to run the new link. The embryonic (and as yet unnamed) RER was not properly conceived until the 1965 {{lang|fr|Schéma directeur d'aménagement et d'urbanisme}} (roughly: 'master plan for urban development'), which envisioned an H-shaped network with two north–south routes.<ref>{{cite web |url=https://www.institutparisregion.fr/documents-historiques-de-reference/schema-directeur-damenagement-et-durbanisme-de-la-region-de-paris-sdaurp/ |title=Schéma directeur d'aménagement et d'urbanisme de la région de Paris (SDAURP) |publisher=institutparisregion.fr |access-date=28 May 2023}}</ref> Between 1969 and 1970, RATP purchased the Vincennes and Saint-Germain lines from SNCF, as the basis for the east–west link.{{CN|date=May 2023}} Only a single north–south route crossing the [[Rive Gauche|Left Bank]] has so far come to fruition, although the Métro's line 13 has been extended to perform a similar function.

The RER's first phase of construction during the 1960s and 1970s was marked by scale and expense. In 1973 alone, [[French franc|FRF]] 2 billion were committed to the project in the budget, equating to roughly €1.37 billion in 2005 terms, and closer to double that as a proportion of the region's (then much smaller) economic output.{{r|cg2003|p=77|q=corresponding to around 9 billion francs in 2000}} The construction cost was controversial at the time of its construction.<ref name="bbc summary2004"/> This initial investment, along with subsequent spending, was partly financed by the ''[[versement transport]]'', a local tax levied on businesses that was introduced in July 1971. It has remained in effect into the twenty-first century.<ref>{{cite web |url = http://acegi.fr/Doc_Paie/Versement_transport.pdf |title = Versement transport |publisher = ACGEI |access-date = 11 November 2011 |url-status = dead |archive-url = https://web.archive.org/web/20120425154900/http://acegi.fr/Doc_Paie/Versement_transport.pdf |archive-date = 25 April 2012 |df = dmy-all }}</ref>

===First phase===

During the first phase of construction, the Vincennes and Saint-Germain lines became the ends of the east-west [[RER A|Line A]], the central section of which was opened station by station between 1969 and 1977. On its completion, Line A was joined by the initial southern section of the north-south [[RER B|Line B]]. Both Lines A and B were intentionally designed to converge with as many of the existing commuter lines as possible as to maximise its usefulness to existing travelers.<ref name="Blakely 11">Blakely 1993, p. 11.</ref> During this first phase, six new stations were built, three of which are entirely underground.

Construction was inaugurated by [[Robert Buron]], then Minister for Public Works, at the [[Pont de Neuilly]] on 6 July 1961, four years before the publication of the official network blueprint. The rapid expansion of the [[La Défense]] business district in the west made the western section of the first line a priority. [[Nation (Paris Métro and RER)|Nation]], the first new station, was opened on 12 December 1969 and became for the next 8 years the new western terminus of the Vincennes line.<ref>{{cite magazine |title = Deep-Level Underground for Paris |magazine = [[The Railway Magazine]] |issue = 826 |date = February 1970 |pages = 80–83}}</ref><ref name="official hist">{{cite web |url = https://www.iledefrance-mobilites.fr/en/about-us/history |title = About us: History |date = 22 July 2021 |publisher = Île-de-France Mobilités |access-date = 28 May 2023}}</ref> The section from [[Charles de Gaulle–Étoile station|Étoile]] (not yet renamed after [[Charles de Gaulle]]) to {{stn|La Défense}} was opened a few weeks later. It was later extended eastward to the newly built {{stn|Auber}} on 23 November 1971, and westward to [[Gare de Saint Germain-en-Laye|Saint-Germain-en-Laye]] on 1 October 1972. The latter extension was achieved by a connection to the existing Saint-Germain-en-Laye line, the oldest railway line into Paris, at [[Nanterre]].<ref>{{cite magazine |title = The Underground Revolution |magazine = [[Rail (magazine)|Rail Enthusiast]] |issue = 23 |date = August 1983 |pages = 8–10}}</ref>

The RER network was inaugurated on 8 December 1977 with the joining of the eastern {{stn|Nation}}-[[Boissy-Saint-Léger station|Boissy]] segment and the western {{stn|Auber}}–{{stn|Saint-Germain-en-Laye}} segment at {{stn|Châtelet–Les Halles}}. The inauguration was attended by President [[Valery Giscard D'Estaing]].<ref name="bbc summary2004">{{cite web |url = http://news.bbc.co.uk/1/hi/uk/3911207.stm |title = France's answer to Crossrail |publisher = [[BBC News]] |first = Hugh |last = Schofield |date = 20 July 2004}}</ref> The southern ''[[Ligne de Sceaux]]'' was simultaneously extended from [[Gare du Luxembourg (Paris RER)|Luxembourg]] to meet Line A at ''Châtelet – Les Halles'', becoming the new Line B. The system of line letters was introduced to the public on this occasion, though it had been used internally by RATP and SNCF for some time.

===Second phase===

A second phase of construction commenced at the end of the 1970s, which was carried out at a slower pace than the first phase. SNCF gained the authorisation to operate its own routes, which became lines C, D and E. Extensive sections of suburban tracks were added to the network, but only four new stations were built.{{CN|date=May 2023}}

During 1979, [[RER C|Line C]] (along the Left Bank of the Seine) was added, although it almost entirely comprised existing SNCF lines.<ref name="Blakely 11"/> The main civil engineering works performed involved the construction of a connecting link between [[Invalides (Paris RER)|Invalides]] and [[Musée d'Orsay (Paris RER)|Musée d'Orsay]].{{CN|date=May 2023}} In 1981, [[RER B|Line B]] was extended through to Gare du Nord via a new deep tunnel from [[Gare de Châtelet – Les Halles|Châtelet – Les Halles]]. It was later extended further northward.<ref>{{Cite magazine |date = January 1995 |title = World Update |magazine = [[Railway Age]] |page = 68}}</ref><ref>Dienel 2004, p. 193.</ref> By 1992, a total of 233 miles of track was operational, while a further 94 miles were under construction.<ref name="Blakely 11"/>

During 1995, [[RER D|Line D]] (north to south-east via Châtelet – Les Halles) was completed; its primary feature was a purpose-built deep tunnel between Châtelet – Les Halles and [[Gare de Lyon]].<ref>[https://web.archive.org/web/20080422005605/http://www.ina.fr/archivespourtous/index.php?vue=notice&id_notice=PAC9826327507 INA - Report on the new RER D]</ref> No new building work was necessary at Châtelet – Les Halles, as additional platforms for Line D had been built at the time of the station's construction 20 years earlier. In 1999, [[RER E|Line E]] was added to the network, connecting the north-east with [[Gare Saint-Lazare]] by means of a new deep tunnel from [[Gare de l'Est]].{{CN|date=May 2023}}

==Maps==
[[File:Central RER network before May 2024 RER E extention.png|thumb|650px|center|Central network of the RER at a geographically accurate scale before RER E extension in 2024]]
[[File:Paris RER.svg|thumb|650px|center|Map of the network showing the outline of [[Île-de-France]]]]

==Rolling stock==
The predominance of suburban SNCF track on the RER network explains why RER trains use [[overhead line]] power and run on the left, like SNCF trains (except in [[Alsace-Moselle]]), contrary to the [[Paris Métro|Métro]] where trains use [[third rail]] power and run on the right. RER trains run by the two different operators share the same track infrastructure, a practice called interconnection. On the RER, interconnection required the development of specific trains ([[MI 79]] series for {{lang|fr|Materiel d'Interconnexion}} 1979, and [[MI 2N]] series for {{lang|fr|Materiel d'Interconnexion à 2 niveaux}} (double-deck interconnection stock)) capable of operating under both 1.5 kV direct current on the [[RATP Group|RATP]] network and 25 kV / 50&nbsp;Hz alternating current on the SNCF network. The [[MS 61]] series ({{lang|fr|Matériel Suburbain 1961}}) can be used only on the 1.5 kV DC network.

The RER's tunnels have unusually large cross-sections. This is due to a 1961 decision to build them according to a [[loading gauge]] standard created by the {{lang|fr|[[Union Internationale des Chemins de Fer]]}} (UIC), with space for overhead [[overhead lines|catenary]] power supply to trains. Single-track tunnels measure {{convert|6.30|m|abbr=on}} across and double-track tunnels up to {{convert|8.70|m|abbr=on}}, meaning a cross-sectional area of up to {{convert|50|m2}}, larger than that of the {{lang|fr|stations}} on many comparable underground rail networks.{{r|cg2003|p=29}}

The first RER rolling stock in fact predated the formation of the RER by 40 years, with the [[Z 23000]] stock used on the {{lang|fr|[[ligne de Sceaux]]}} (which was thereafter integrated into [[RER B]]) from 1937 until 27 February 1987. In 1965 the [[SNCF Class Z 5300|Z 5300]] train was introduced, followed by the [[MS 61]] in 1967, [[MI 79]] in 1980, [[MI 84]] and [[SNCF Class Z 8800|Z 8800]] in 1985, [[SNCF Class Z 20500|Z 20500]] in 1988, [[MI 2N]] in 1996, [[SNCF Class Z 20900|Z 20900]] in 2001, [[MI 09]] on 5 December 2011, [[SNCF Class Z 50000|Z 50000]] (Francilien) in 2015 and [[Regio 2N]] (Z 57000) in 2019. In 2017, it was announced that an consortium comprising [[Alstom]] and [[Bombardier Transportation]] had been selected to supply 255 [[RER NG|X’Trapolis Cityduplex]] [[Bilevel rail car|double-deck]] [[electric multiple unit]]s to replace aging rolling stock on both lines D and E under a €3.75 billion arrangement.<ref>{{cite web |url = https://www.globalrailwayreview.com/news/31211/sncf-ile-de-france/ |title = SNCF selects consortium to supply 255 trains for Île-de-France network |first = Katie |last = Sadler |publisher = globalrailwayreview.com |date = 11 January 2017}}</ref> In April 2023, 60 additional Cityduplexs were ordered to increase service frequency.<ref>{{cite web |url = https://www.railadvent.co.uk/2023/04/alstom-to-supply-sixty-more-new-generation-trains-for-ile-de-france.html |title = Alstom to supply sixty more new-generation trains for Île-de-France |publisher = railadvent.co.uk |first = Janine |last = Booth |date = 27 April 2023}}</ref>

Many services are performed by double-decker train sets, usually operating in double formations.

<gallery class="center" widths="150">
File:Z-22901-idfm-versailles-chantiers.jpg|[[SNCF Class Z 20900|Z 20900]] at Versailles Chantiers ([[RER C]])
File:Z 57000 (Regio 2N) IDF Mobilités Ligne R.jpg|[[Regio 2N|Z 57000]] at Paris Gare de Lyon ([[Transilien Line R]] and [[RER D]])
File:Z50000 IDFM et SNCF Carmillon.jpg|[[SNCF Class Z 50000|Z 50000]] ([[RER E]] and [[Transilien Line P]])
File:Ligne de Nanterre a Sartrouville - Viaduc de Nanterre - MI09 - Avril 2012 (4) cropped.jpg|[[MI 09]] ([[RER A]])
File:MI79-R 8292 1.jpg|[[MI 79]] renovated ([[RER B]])
File:Gare de Corbeil-Essonnes - 2021-07-08 - IMG 7373.jpg|[[Z 20500]] at Corbeil-Essonnes ([[RER D]])
File:Gare de Vauboyen - 2021-09-23 - IMG 0034.jpg|[[SNCF Class Z 20900|Z 20900]] at Vauboyen  ([[RER C]])
File:Gare Bourron-Marlotte - Grez IMG 8615.jpg|[[SNCF Class Z 5600|Z 5600]] at Bourron-Marlotte - Grez ([[Transilien Line R]] and [[RER C]])
File:RER A - Gare AchèresVille 21.JPG|[[Altéo]] at [[Gare d'Achères-Ville|Achères-Ville]] ([[RER A]])
File:RER E - Gare Chelles 4Bis.JPG|[[Z 22500]] at [[Gare de Chelles-Gournay|Chelles-Gournay]] ([[RER E]])
</gallery>

==Lines==
{| class="wikitable sortable" style="text-align:right;"
|+ '''Paris RER lines'''<ref>{{Cite web |date=October 2023 |title=La qualité de service du réseau express régional (RER) en Île-de-France |trans-title=Île-de-France Regional Express Network (RER) service quality |url=https://medias.vie-publique.fr/data_storage_s3/rapport/pdf/291464.pdf |publisher=[[Cour des comptes (France)|French Court of Accounts]] |page=92 |format=PDF}}</ref>
! colspan="2" | Line name
!Operator
! Opened
! Last<br>extension
! Stations
! Trains<br>in service
! Peak {{Abbr|tph|Trains per hour}}
! Length
! Daily ridership
|-
| {{rint|paris|r|A}}
| style="text-align:left;"|[[RER A]]
| style="text-align:left;"|RATP/SNCF{{Efn|Most of the line is operated by the RATP, except the Cergy and Poissy branches which are operated by the SNCF|group=tablenote}}
| 1977
| 1994
| 46
|91
|26
| {{Convert|109|km|mi|abbr=on|sortable=on}}
| {{Formatnum:1400000}}
|-
| {{rint|paris|r|B}}
| style="text-align:left;"|[[RER B]]
| style="text-align:left;"|RATP/SNCF{{Efn|South of the line (from Châtelet–Les-Halles southwards) operated by the RATP, north (from Gare du Nord northwards) operated by the SNCF|group=tablenote}}
| 1977
| 1981
| 47
|147
|20
| {{Convert|80|km|mi|abbr=on|sortable=on}}
| {{Formatnum:983000}}
|-
| {{rint|paris|r|C}}
| style="text-align:left;"|[[RER C]]
| style="text-align:left;"|SNCF
| 1979
| 2000
| 84{{Efn|Before the section between Epinay-sur-Orge, Massy-Palaiseau, and Versailles-Chantiers was transferred to the T12 and Transilien V.|name=epinaymassyversailles|group=tablenote}}
|172
|20
| {{Convert|187|km|mi|abbr=on|sortable=on}}{{Efn|Before the section between Epinay-sur-Orge, Massy-Palaiseau, and Versailles-Chantiers was transferred to the T12 and Transilien V.|name=epinaymassyversailles|group=tablenote}}
| {{Formatnum:540000}}
|-
| {{rint|paris|r|D}}
| style="text-align:left;"|[[RER D]]
| style="text-align:left;"|SNCF
| 1987
| 1995
| 54{{Efn|Within [[Île-de-France]] only; full line is 59 stations and {{convert|197|km|mi|abbr=on}}.|name=idfonly|group=tablenote}}
|134
|12
| {{Convert|172|km|mi|abbr=on|sortable=on}}{{Efn|name=idfonly|group=tablenote}}
| {{Formatnum:660000}}
|-
| {{rint|paris|r|E}}
| style="text-align:left;"|[[RER E]]
| style="text-align:left;"|SNCF
| 1999
| 2024
| 25
|64
|22
| {{Convert|60|km|mi|abbr=on|sortable=on}}
| {{Formatnum:350000}}
|}
{{Notelist|group=tablenote}}

==Stations==<!-- This section is linked from [[RER]] -->
{{Main|List of Réseau Express Régional stations}}
Ten new stations have been built under the heart of Paris since the 1960s as part of the RER project. The six stations of [[RER A|Line A]] opened between 1969 and 1977 are:

* {{stn|Nation}} (1969): deep construction at the {{lang|fr|Place de la Nation}}.
* {{stn|Charles de Gaulle–Étoile}} (1970): deep construction at the [[Arc de Triomphe]].
* {{stn|La Défense}} (1970): near-surface construction beneath the site of the yet-to-be-built [[Grande Arche|Grande Arche de la Défense]], just outside the Paris city boundary.
* {{stn|Auber}} (1971): deep construction near [[Gare Saint-Lazare]].
* {{stn|Châtelet–Les Halles}} (1977): near-surface construction on the site of the former marketplace, claimed in 2017 to be the largest underground station in Europe.<ref>{{cite web |title = Ouverture de la Porte Marguerite de Navarre, nouvel accès direct à la gare de Châtelet-Les Halles |url = https://www.ratp.fr/groupe-ratp/newsroom/innovation/ouverture-de-la-porte-marguerite-de-navarre-nouvel-acces-direct-la |publisher = RATP}}</ref>
* [[Gare de Lyon]] (1977): near-surface construction beneath and alongside the main-line SNCF station.

[[File:RER-B at Charles de Gaulle.jpg|thumb|[[RER B|Line B]] station at [[Aéroport Charles de Gaulle 2 – TGV|Aéroport Charles de Gaulle 2]].]]

Some controversy followed the construction of the Line A. Using the model of the existing [[Paris Métro|Métro]], and unlike any other underground network in the world, engineers elected to build the three new deep stations ([[Charles de Gaulle–Étoile station|Étoile]], {{stn|Auber}} and {{stn|Nation}}) as single monolithic halls with lateral platforms and no supporting pillars. A hybrid solution of adjacent halls was rejected on the grounds that it "completely sacrificed the architectural aspect" of the oeuvre.{{r|cg2003|p=31}}{{r|grp=Notes|n1}} The scale in question was vast: the new {{lang|fr|stations cathédrales}} were up to three times longer, wider and taller than Métro stations, and hence 20 or 30 times more voluminous. Most importantly, unlike the Métro they were to be constructed deep underground. The decision turned out to be expensive: around 8 billion francs for the three stations, equivalent to €1.2 billion in 2005 terms, with the two-level {{stn|Auber}} the costliest of the three.{{r|cg2003|p=34}} The comparison was obvious and unfavourable with London's [[Victoria line]], a deep line of {{convert|22|km|0|abbr=on}} constructed during the same period using a two-tunnel approach at vastly lower cost though with a lower capacity. However, the three stations represent undeniable engineering feats and are noticeably less claustrophobic than traditional underground stations.{{citation needed|date=January 2023}}

[[File:RER-E Haussmann 2.jpg|thumb|{{stn|Haussmann–Saint-Lazare}} on the [[RER E|RER&nbsp;E]]]]

Only two stations were inaugurated to complete Lines [[RER B|B]], [[RER C|C]] and [[RER D|D]]:

* [[Gare du Nord]] (1982): near-surface construction on two levels.
* [[Gare de Saint-Michel – Notre-Dame|St-Michel – Notre-Dame]] (1988): deep construction on an existing stretch of the Line B between [[Gare du Luxembourg (Paris RER)|Luxembourg]] and [[Gare de Châtelet – Les Halles|Châtelet – Les Halles]] with two tunnels, common in other underground systems but unique in Paris. The station is situated on and built at the same time as the [[Gare du Luxembourg (Paris RER)|Luxembourg]] [[Gare de Châtelet – Les Halles|Châtelet]] tunnel.

Two stations were added to the network as part of [[RER E|Line E]] in the 1990s. They are notable for their lavishly spacious deep construction, a technique not used since {{stn|Auber}}. Although similar to the three 1960s "cathedral stations" of Line A, their passenger traffic has so far proved vastly lower.

* {{stn|Magenta}} (1999): deep construction serving both {{lang|fr|Gare du Nord}} and [[Gare de l'Est]].
* {{stn|Haussmann–Saint-Lazare}} (1999): deep construction serving [[Gare Saint-Lazare]] and ''Auber''.

==Usage==
[[File:Inside the RER B going to Paris - 2019-02-14.jpg|thumb|An overcrowded RER B train]]
Journey times, particularly on east-west and north-south routes, have been reduced by the RER; in combination with the cross-platform connection at [[Gare de Châtelet – Les Halles|Châtelet – Les Halles]], even certain "diagonal" trips have reduced journey times.{{citation needed|date=March 2017}} Typically being used for leisure journeys, the RER has made a significant social impact. By bringing far-flung suburbs within easy reach of central Paris, the network has aided the reintegration of the traditionally insular capital with its periphery. Evidence of this social impact can be seen at Châtelet – Les Halles, whose neighbourhood and [[Forum des Halles]] leisure and shopping facilities are popular among {{lang|fr|[[banlieue|banlieusards]]}}, in particular from eastern suburbs.<ref>{{cite book |last = Large |first = Pierre-François |title = Des Halles au Forum: Métamorphose au coeur de Paris |year = 2013 |publisher = Harmattan |page = 102}}</ref>

Lines [[RER A|A]] and [[RER B|B]] reached saturation relatively quickly, exceeding by far all traffic expectations: up to 55,000 passengers per hour in each direction on Line A (1992), the highest such figure outside of East Asia.{{r|cg2003|p=61}} Despite a frequency of more than one train every two minutes, made possible by the installation of digital signalling in 1989, and the gradual introduction of double-decker trains from 1998 to 2017, the central stations of Line A are critically crowded at peak times.<ref>{{in lang|fr}} [[:fr:Système d'aide à la conduite, à l'exploitation et à la maintenance|SACEM signalling]] on the [[French Wikipedia]]</ref> In June 2015, a contract valued at €20 million was awarded to [[Alstom Transport]] to develop and install an [[automatic train operation]] (ATO) system on [[RER A]]; at the time, this line was the most heavily frequented regional line in Europe, the introduction of ATO enabled increased service frequency and improved performance to be achieved.<ref>{{cite web |url = https://www.intelligenttransport.com/transport-news/16341/automatic-train-operation-to-be-installed-on-line-a-of-paris-rer/ |title = Automatic train operation to be installed on Line A of Paris RER |first = Katie |last = Sadler |publisher = intelligenttransport.com |date = 11 June 2015}}</ref>

The RER has a substantial impact on the suburban areas of greater Paris, specifically on land values near the stations along its lines.<ref>European Conference of Ministers of Transport 1980, pp. 44–45.</ref> The RER has received criticism for its high level of [[particles and Pollution|particle pollution]] during busy periods, largely due to train braking. Pollution by [[PM10]] particles regularly reaches 400&nbsp;μg/m<sup>3</sup> at {{stn|Auber}},<ref>{{cite web |url = http://data.ratp.fr/fr/les-donnees.html |title = Les données &#124; Plateforme opendata de la RATP |access-date = 24 March 2013 |url-status = dead |archive-url = https://web.archive.org/web/20130308043233/http://data.ratp.fr/fr/les-donnees.html |archive-date = 8 March 2013 |df = dmy-all }}</ref> much more than at neighboring metro stations and eight times the [[EU Commission]]'s daily average limit <ref>EU Directives [http://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:31999L0030&from=EN 1999/30/EC, Annex III] and [http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:31996L0062 96/62/EC, the Air Quality Framework Directive]</ref> of 50&nbsp;μg/m<sup>3</sup>.

==See also==
{{Portal|Trains|France}}
* [[List of metro systems]]
* [[List of RER stations]]
* [[List of Paris Métro stations]]
* [[Réseau Express de l'Aire urbaine Lyonnaise]]
* [[Transport in France]]
* [[Île-de-France tramway Line 11 Express]]
* [[S-train]]
* [[Réseau Ferré National (France)|Réseau Ferré National]]
* [[Grigny to Corbeil-Essonnes line]]

==Notes==
{{Reflist|group=Notes|refs=
<ref name=n1>Internal RATP journal #226, October 1966</ref>
}}

==References==
===Citations===
{{Reflist|refs=
<ref name="cg2003">{{cite book |last1 = Gerondeau |first1 = Christian |title = La Saga du RER et le maillon manquant |date = 2003 |publisher = Presse de l'École nationale des ponts et chaussées |isbn = 2-85978-368-7}}</ref>
}}

===Bibliography===
* {{cite book |first1 = Chloé |last1 = Vitry |first2 = Daniel J. |last2 = Sage |url = https://books.google.com/books?id=9C1dDwAAQBAJ |title = Societies Under Construction |date = 2018 |publisher = Springer International |isbn = 978-3319739960}}
* {{cite book |first = Edward James |last = Blakely |title = Transporting and Transforming a Nation: Issues 584–596 |date = 1993 |url = https://books.google.com/books?id=DzUYnN_BDy8C |publisher = University of California}}
* {{cite book |author = European Conference of Ministers of Transport |title = ECMT Round Tables Transfers Through the Transport Sector |url = https://books.google.com/books?id=g6Fv4WStg64C |date = 1980 |publisher = OECD |isbn = 9282105121}}
* {{cite book |last1 = Dienel |first1 = Hans-Liudger |title = Unconnected Transport Networks: European Intermodal Traffic Junctions 1800-2000 |date = 2004 |publisher = Campus Verlag |isbn = 359337661X}}

==Further reading==
* {{cite book |last1 = Gaillard |first1 = Marc |title = Du Madeleine-Bastille à Météor: Histoire des transports Parisiens |date = 1991 |publisher = Martelle |isbn = 2-87890-013-8}}

==External links==
{{Commons and category}}
{{Rapid transit OSM map|display=title|text=Network map}}
* [https://www.ratp.fr/ RATP] (official, in {{in lang|fr}})
* [https://www.ratp.fr/en/ RATP] (official, in {{in lang|en}})
* [https://www.ratp.fr/en/plan-rer Interactive Map of the RER] (from RATP's website)
* [https://www.ratp.fr/en/plan-metro Interactive Map of the Paris métro] (from RATP's website)
* [https://cartometro.com/cartes/rer-idf/ Complete track map of the RER system] by Franklin Jarrier, 10 November 2015

{{Paris}}
{{Paris transport network}}
{{Paris Rail Stations}}
{{RER rolling stock}}
{{RATP Group}}
{{International Metro Organizations}}
{{Authority control}}
{{coord missing|France}}

{{DEFAULTSORT:Reseau Express Regional}}
[[Category:Réseau Express Régional| ]]
[[Category:Electric railways in France]]
[[Category:RATP Group]]
[[Category:Underground commuter rail]]