Explore Techsciencenews Encyclopedia Alphabetically

Techsciencenews Home 


Art | Business Studies | Citizenship | Countries | Design and Technology | Everyday life | Geography | History | Information Technology | Inventions Timeline | Language and Literature | Mathematics | Music | People | Portals | Religion | Science | Subjects Index


Related subjects Railway transport

Paris public transport
Métro lines
line 1 line 7bis
line 2 line 8
line 3 line 9
line 3bis line 10
line 4 line 11
line 5 line 12
line 6 line 13
line 7 line 14
RER lines
line A line D
line B line E
line C
Suburban rail (Transilien)
Saint-Lazare Nord
La Défense Est
Montparnasse Lyon
Airport shuttles
CDGVAL Orlyval
Bus (RATP) Noctilien
  Bus (Optile)  
Tramway T1 Tramway T2
Tramway T3 Tramway T4

The RER (Réseau Express Régional, IPA [ɛʀøɛʀ], "Regional Express Network") is a rapid transit system serving Paris, France. The RER is an integration of a modern city-centre subway and a pre-existing set of regional rail lines. Within the city of Paris, the RER serves as an express network, offering multiple connections with the Paris Métro. The central part of the RER was completed through a massive civil engineering effort between 1962 and 1977, and features some unusually spacious, deep stations. In 2007 the network consisted of five lines: A, B, C, D and E. The RER is still expanding — Line E was opened in 1999, and is a likely candidate for extension.

The RER currently serves 257 stops and runs over 587 km (365 miles) of track, including 76.5 km (48 miles) underground. Thirty-three stops are within the city of Paris. Each line crosses the city almost exclusively underground and on dedicated tracks. Some parts of RER lines are operated by the city transport authority that operates the Métro ( RATP) and others by the national rail company ( SNCF); the differences are of little concern to riders during normal operations because of the seamless fare structure and absence of transfers at SNCF/RATP boundaries. In 2004, 782.9 million journeys were made on the RER.

The RATP operates 66 RER stations, Line B south of Gare du Nord, (all south branches) and line RER A (all east branches), and the west branch to Saint Germain en Laye from Nanterre Prefecture. All RER track on lines RER A and RER B within Paris are maintained and operated by RATP.

SNCF RER D interlaces with RER B RATP rolling stock by sharing RATP track slots on line RER B between Gare du Nord and Chatelet. On the sections of shared track, each company operates separately. Therefore, the SNCF RER operates on RFF track and the RATP on its own. Of these RATP RER stations, 9 possess interchanges with Metro lines, and 9 with the Transilien SNCF service.

The RATP celebrated the 30th anniversary of the opening of the RER A and RER B junction December 8, 2007.



The origins of the RER can be traced back to the 1936 Ruhlmann- Langewin plan of the Compagnie du chemin de fer métropolitain de Paris (Metropolitan Railway Company of Paris) for a wide-bodied "métropolitain express" (express metro). The CMP's post-war successor, the RATP, revived the scheme in the 1950s, and in 1960 an interministerial committee decided to go ahead with construction of a first, east-west, line. As its instigator, the RATP was granted authority to run the new link and the SNCF ceded operation of the Saint-Germain-en-Laye line (to the west of Paris) and the Vincennes line (to the east). The embryonic (and as yet unnamed) RER was not properly conceived until the 1965 Schéma directeur d'aménagement et d'urbanisme, which foresaw an "H"-shaped network with two north-south routes. Only a single north-south axis crossing the Left Bank has so far come to fruition, although the Métro's Line 13 has been extended to perform a similar function.


In the first phase of construction, the Saint-Germain and Vincennes lines became the ends of the east-west Line A, whose central section was opened station by station between 1969 and 1977. On its completion Line A was joined by the initial southern leg of the north-south Line B. During this first phase, six new stations were built, three entirely underground and all on a grand scale.

Construction was ceremonially inaugurated by Robert Buron, 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 this western section of the new east-west route a priority. Such was the scale of the work that it was not until 12 December 1969 that the first new station — and the RER name — was inaugurated, at Nation on the eastern section. Nation thus became temporarily the new terminus of the Vincennes line from Boissy. A few weeks later came the long-awaited opening of the western line from Étoile (not yet renamed after Charles de Gaulle) to La Défense. A simple shuttle service, this western section was extended eastward to the newly-built central Auber station on 23 November 1971, and westward on 1 October 1972 to Saint-Germain-en-Laye through a connection to the Saint-Germain-en-Laye line, the oldest railway line into Paris, at Nanterre.

The RER network truly came into being on December 9, 1977 with the joining of the Nation- Boissy and Auber- Saint-Germain-en-Laye segments as the eastern and western halves of the RER Line A at Châtelet - Les Halles in the heart of Paris. The southern Ligne de Sceaux was simultaneously extended from 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 at RATP and SNCF for some time.


A second phase, from the end of the 1970s, was of more soberly paced completion. The SNCF gained the right to operate its own routes, which became lines C, D and E. Extensive sections of suburban track were added to the network but only four new stations were built. Of these, two were comparable in audaciousness to those of the 1970s. The network was completed in the following stages:

  • Line C (following the Left Bank of the Seine) was added in 1979, involving the construction of a short cut-and-cover link between Invalides and Musée d'Orsay.
  • Line B extension to the Gare du Nord (1981) and the north (1983) was effected by a new deep tunnel from Châtelet - Les Halles.
  • Line D (north to south-east, via Châtelet – Les Halles) was completed in 1995, using a new deep tunnel between Châtelet – Les Halles and Gare de Lyon. No new building work was necessary at Châtelet – Les Halles, since, in an example of superb planning, additional platforms for Line D had been built at the time of the station's construction 20 years earlier.
  • Line E was added in 1999, connecting the north-east with Gare Saint-Lazare by means of a new deep tunnel from Gare de l'Est.


Two aspects of the RER's pioneering phase in the 1960s and 1970s are particularly noteworthy. The first is the spectacular scale and expense of the enterprise. For example, FRF 2 billion were committed to the project in the budget of 1973 alone. This equates 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. This and subsequent spending is partly explained by the regional transport contribution, a small levy made on businesses that evidently benefit from the vast labour market put at their disposal by the RER. This peculiarly French invention was passed by a law in June 1971 and has been a permanent source of revenue for transport investment ever since.

Second, it is striking how little public consultation was made over such expenditures and tax innovations. Contrary to the lively public debate that accompanied the building of the Métro 70 years previously, the RER aroused little media attention and was essentially decided behind the closed doors of cabinet meetings. The will, and even idealism, of a handful of people, notably Pierre Giraudet, Director-General of the RATP, proved decisive in persuading ministers to grant credits. So too did the united front presented by the RATP and SNCF and their success at keeping within their budgets. Given the subsequent success of the RER, the investment can be considered money well spent.


Central network of the RER at a geographically accurate scale
Central network of the RER at a geographically accurate scale
Vector map of the network
Vector map of the network


The RER B at La Plaine - Stade de France.
The RER B at La Plaine - Stade de France.

The predominance of suburban SNCF track on the RER network explains why RER trains drive on the left, like SNCF trains (except in Alsace-Moselle), contrary to the Métro where trains drive 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 Materiel d'Interconnexion 1979, and MI 2N series for Materiel d'Interconnexion à 2 niveaux (double-deck interconnection stock)) capable of operating under both 1.5 kV direct current on the RATP network and 25 kV / 50 Hz alternating current on the SNCF network. The MS 61 series (Matériel Simple 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 according to a standard set by the Union Internationale des Chemins de Fer, with space for overhead catenary power supply to trains. Single-track tunnels measure 6.30 m across and double-track tunnels up to 8.70 m, meaning a cross-sectional area of up to 50 square metres, larger than that of the stations on many comparable underground rail networks.


RER B station of Aéroport Charles de Gaulle 2.
RER B station of Aéroport Charles de Gaulle 2.
Paris RER lines
Line Name Opened Last
Length Average
Journeys made
(per annum)
Line A 1977 1994 46 108.5 km / 67.5 miles 2,411 m 272,800,000
Line B 1977 1981 47 80.0 km / 49.8 miles 1,739 m 165,100,000
Line C 1979 2000 84 185.6 km / 115.5 miles 2,184 m 140,000,000
Line D 1987 1995 59 160.0 km / 99.6 miles 2,807 m 145,000,000
Line E 1999 2003 21 52.3 km / 32.5 miles 2,615 m 60,000,000


Ten new stations have been built under the heart of Paris since the 1960s as part of the RER project. The six stations of Line A opened between 1969 and 1977 are:

  • Nation (1969): deep construction at the Place de la Nation
  • Charles de Gaulle - Étoile (1970): deep construction at the Arc de Triomphe
  • La Défense (1970): near-surface construction beneath the site of the yet-to-be-built Grande Arche de la Défense, just outside the Paris city boundary
  • Auber (1971): deep construction near Gare Saint-Lazare; once the largest underground station in the world
  • Châtelet - Les Halles (1977): near-surface construction on the site of the former marketplace, today perhaps the largest underground station in the world
  • Gare de Lyon (1977): near-surface construction beneath and alongside the main-line SNCF station

Some controversy followed the construction of the Line A. Using the model of the existing Métro, and unlike any other underground network in the world, engineers elected to build the three new deep stations ( Étoile, Auber and 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. The scale in question was vast: the new 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 entirely underground. The decision turned out to be expensive - around FFr 8 billion for the three stations, equivalent to € 1.2 billion in 2005 terms, with the two-level Auber the costliest of the three. The comparison was obvious and unfavourable with London's Victoria Line, a deep line of 22 km constructed during the same period using a two-tunnel approach at vastly lower cost. However, the three stations represent undeniable engineering feats and are noticeably less claustrophobic than traditional underground stations.

Haussmann - Saint-Lazare on the RER E.
Haussmann - Saint-Lazare on the RER E.

Only two stations were inaugurated to complete Lines B, C and D:

  • Gare du Nord (1982): near-surface construction on two levels
  • St-Michel - Notre-Dame (1988): deep construction on an existing stretch of the Line B between Luxembourg and Châtelet - Les Halles with two tunnels, common in all other deep underground systems but unique in Paris. The station was actually built when the Luxembourg_ Châtelet tunnel was dug as an enlargement of the tunnel itself. As this station is under the Seine river, it has a very narrow platform much alike London Underground stations, and does not sport the usual architectural expanse of other stations.

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

  • Magenta (1999): deep construction serving both Gare du Nord and Gare de l'Est
  • Haussmann - Saint-Lazare (1999): deep construction serving Gare Saint-Lazare and Auber


The social and economic impact of the RER is difficult to overstate. Journey times, particularly on east-west and north-south routes, have been cut spectacularly (and thanks to the cross-platform connection at Châtelet - Les Halles, even "diagonal" trips are rapid). As a result, the network has been an extraordinary popular success since its opening.

Lines A and B reached saturation relatively quickly, exceeding by far all traffic expectations: up to 55,000 passengers per hour in each direction on Line A, the highest such figure in the world outside Japan. Despite a frequency of more than one train every two minutes, made possible by the installation of digital signalling in 1989, and the partial introduction of double-decker trains since 1998, the central stations of Line A are critically crowded at peak times. Since both Métro and surface transport are equally congested at these times (and significantly slower), the RER's value to the economy of Île de France cannot be in doubt.

Used for leisure journeys, the RER represents no less of a revolution. By bringing far-flung suburbs within easy reach of central Paris, the network has significantly aided the reintegration of the traditionally insular capital with its periphery. The evidence of this social impact can be seen at Châtelet - Les Halles, whose neighbourhood is now crowded with suburbanites on evenings and weekends.

Future developments

Utopic vision for the RER in 2025
Utopic vision for the RER in 2025

Extensions to the RER focus on Line E, which ends at Haussmann - Saint-Lazare, serving only one side of Paris, unlike all other RER lines. Various Line E extensions have been proposed:

  • eastwards from Chelles-Gournay to Esbly and Meaux
  • eastwards from Tournan to Coulommiers
  • westwards from Haussmann - St Lazare to Saint-Nom-la-Bretèche and Versailles Rive-Droite, via a new station at Champs-Elysées - Clémenceau and Gare Montparnasse.

A new Line E station has been proposed at Rue de l'Évangile on the approach to Gare de l'Est, with a tentative opening date of 2014.

Older plans existed for a line F, which would connect Argenteuil to Rambouillet via existing tracks of the Saint-Lazare and Montparnasse rail networks. A new tunnel would be bored below Paris, with the creation of a station at Invalides. The cost of the new tunnel, and the fact that Saint-Lazare and Montparnasse networks form a loop makes this project unlikely to happen.

International comparison

Locale Paris
Transit type Rapid transit Regional rail
Began operation 1977
System length 587 km (365 mi)
Number of lines 5
Number of stations 257
Track gauge 1,435 mm (4 ft 8½ in) ( standard gauge)
Operator(s) RATP, SNCF

The RER is often compared with other urban rail networks that serve outer suburbs while fully crossing the city. Examples included the German and Austrian S-Bahnen, the Spanish Cercanías, and the RER networks of French-speaking Switzerland and (in construction) Brussels.

However, there are two characteristics of the Paris RER that are not found in most other systems. Firstly, each RER line runs on independent dedicated track (except the tunnel between Gare du Nord and Châtelet, used by both lines B and D), with dedicated platforms in stations that are shared with other networks. This feature allows a high frequency, which on some lines exceeds that of the Paris Métro — a situation which in Europe is unique to Paris.

Secondly, the Paris RER serves almost exclusively the Paris urban area, reaching very few satellite towns. The exceptions are the Southern branch of line C and the outer sections of line D. The compactness of the Paris conurbation can account for a good deal of the RER's more limited reach, as can the sprawling nature of the suburban SNCF network. This also explains why the scheduled train frequencies on the RER central network are as high as on the Paris métro network; one train every 120 seconds on RER A during rush hour .

Retrieved from " http://en.wikipedia.org/wiki/RER"