Traffic (2007): 300,000,000 journeys per annum (figure for both the RATP and SNCF section of the line)
Line A is one of the world's busiest lines, and the busiest line in Europe with over 1,200,000 passengers per day. It is formed from the connection of the Saint-Germain-en-Laye-Nanterre line in the west to the Vincennes – Boissy-St-Léger line in the east. Two branches were added in the west, to Poissy and the new town of Cergy-Pontoise, and in the east to the new town of Marne-la-Vallée. The two latest extensions were to Cergy-Le Haut and Disneyland Paris.
paris mi09 rer a nation dyla
Popular success and responses
With more than one million passengers per workday, line A is the busiest Parisian RER and metro line. Ever-increasing traffic volume and the need to ward off imminent saturation have been major factors in RATP and SNCF's planning since the inauguration of the line. At least five major capital investment decisions can be directly traced back to this issue:
In the early 1980s RATP contracted German conglomerate Siemens to develop a dynamic traffic control system that would remove the capacity constraints caused by conventional block traffic management. SACEM (Système d'aide à la conduite, à l'exploitation et à la maintenance) is still one of the most advanced traffic control systems and enables extremely short spacing (under 90 seconds in stations, under 2 minutes in tunnels) between trains during rush hour. Parisians have become used to the sight of a train pulling into a station as the one before it is just clearing the platform.
Around the same time, RATP ordered a significant number of MI79/MI84 trains to remedy premature wear and tear on MS61 stock caused by over-utilization on Line A.
Later in the 1980s, the need to relieve congestion on the central segment of Line A was a key factor in selecting the route of the new, fully automated Paris Métro Line 14 (also known as METEOR).
The same need governed the choice of the route of RER Line E in the early 1990s and is a factor in plans for that line's westward or south-westward extension.
A new class of double-deck trains (MI 2N series) entered service in 1998, in part a product of RATP's belief that no further infrastructure improvement (short of an extremely expensive track quadrupling of the central section) would relieve congestion on Line A. This was followed in 2011 by the MI 09 double-decker stock, aimed at replacing the aging MI 84 and MS 61 stocks.
One simple (if partial) solution to the congestion problem that has never been implemented is a change in the seating configuration in the trains. The RER is unusual among high-capacity urban train networks in its attachment to transverse (front and back facing) seating. A change to longitudinal (sideways window-lining) seating typically reduces the number of seats by 10% but increases standing room by 30%. The result is increased capacity and a less cramped ride for those without seats.
Chronology
14 December 1969: RATP buys the "ligne de Vincennes" from SNCF, connecting Bastille with Boissy-Saint-Léger in the east. A new 2.5-km tunnel between Vincennes and Nation, which replaces Bastille as the terminus. Length: 17.5 km.
21 February 1970: RATP buys the "ligne de St-Germain" from SNCF, connecting the Gare Saint-Lazare with Saint-Germain-en-Laye in the west. A new tunnel between La Défense and the Place de l'Étoile, which replaces St-Lazare as the terminus. Shuttle ("navette") service is operated La Défense – Étoile, 4 km.
23 November 1971: Tunnel opened Étoile – Auber, 2 km. Shuttle service extended to operate La Défense – Auber.
1 October 1972: Tunnel opened La Défense – Nanterre-Université, 2 km. Shuttle service extended on the "ligne de St-Germain" (La Défense – Saint-Germain-en-Laye, 13 km) to operate Saint-Germain – Auber.
October 1973: New underground station, Nanterre-Préfecture, between La Défense and Nanterre-Université.
9 December 1977: The lines are connected by a 6-km tunnel, giving birth to the RER A line, Saint-Germain – Boissy-Saint-Léger, 42.5 km. Two new stations: Châtelet-les Halles and Gare de Lyon. A new branch, "ligne nouvelle de Marne-la-Vallée", 8.5 km, in the east from Vincennes to Noisy-le-Grand.
19 December 1980: The "ligne nouvelle de Marne-la-Vallée" extended from Noisy-le-Grand to Torcy, 9 km.
29 May 1988: New service, "Interconnexion Ouest", Cergy-St-Christophe – Marne-la-Vallée (Torcy), 47 km. New branch in the west from Nanterre-Préfecture to Cergy-St-Christophe, 15.5 km.
May 1990: A branch in the west from Maisons-Laffitte to Poissy, 8.5 km.
1 April 1992: The Marne-la-Vallée line extended from Torcy to Marne-la-Vallée-Chessy, 11 km, to create a link from the centre of Paris to Disneyland Paris.
29 August 1994: Extension opened Cergy-St-Christophe – Cergy-Le Haut, 2.5 km. New station, Neuville-Université, between Conflans-Fin-d'Oise and Cergy-Préfecture.
10 June 2001: New station, Val-d'Europe, between Bussy-St-Georges and Marne-la-Vallée-Chessy.
St Germain branch – common trunk line – Boissy branch
Cergy or Poissy branches – common trunk line – Marne la Vallée branch.
During off-peak hours, the Poissy – Noisy services operate every 20 minutes plus a La Défense – Noisy service every 20 minutes, and the St-Germain – Boissy and Cergy – Chessy services operate every 10 minutes.
Operations are very complex during peak periods, with an average of one train every 2 minutes (30 trains / hour) on the common trunk line in the busier direction (east to west in the morning, west to east in the evening), and one train every 2 min 30 sec in the other direction (24 trains / hour). The Marne la Vallée branch has the most intensive service.
Names of services
RER trains display a "nom de mission" or "name of service", not the name of the destination station. These are invented names designating (and distinguishing) individual services ("runs"), and are accompanied by a two-digit number, for example ZARA59 or DJIB72.
The first letter corresponds to the destination (gare d'arrivée):
The second letter corresponds to the stations served and the origin station: a letter can have different meanings, depending on the destination. For instance, second letter "E" indicates:
with first letter "N" or "Z", all stations Saint-Germain-in-Laye – Boissy-St-Léger (NELY or ZEUS);
with first letter "Q", Poissy to Marne-la-Vallée – Chessy, all stations except Neuilly-Plaisance and Bry-sur-Marne (QENO).
The third and fourth letters are used to form a pronounceable name, changed when the service number (odd 01-99 eastward, even 02-98 westward) reaches the maximum. For example, successive trains to Boissy-St-Léger are called NEGE96, NEGE98, then NELY02, NELY04, etc. Each service is uniquely identifiable, as there cannot be two "NEGE" services with the same number in the same day.
Services with the same first two letters serve the same stations, e.g. ZEBU, ZEUS and ZEMA (to Saint-Germain-en-Laye), or NEGE, NELY and NEMO (to Boissy-Saint-Léger). The letters ZZ generally indicate that the established service pattern was changed for an unspecified reason, generally a technical problem which disrupted operations.
Morning Peak
Every 10 minutes:
Boissy – Le Vésinet-Le Pecq, all stations except Nanterre-Ville.
La Varenne – St-Germain, all stations except Chatou-Croissy and Le Vésinet-Centre.
Marne-la-Vallée – Chessy – Cergy-le-Haut, all stations except Lognes, Noisiel, Bry-sur-Marne, Houilles and Maisons-Laffitte.
Marne-la-Vallée – Chessy – Poissy, all stations except Val d'Europe, Bussy-St-Georges, Lognes, Noisy-Champs and Sartrouville.
Torcy – Rueil-Malmaison, all stations except Bry, Neuilly-Plaisance and Nanterre-Préfecture.
Cergy – Torcy, all stations except Maisons-Laffitte, Houilles, Noisiel and Lognes.
Poissy – Chessy, all stations except Neuilly-Plaisance and Bry.
St-Germain – Boissy, all stations except Le Vésinet-Centre and Chatou-Croissy.
Le Vésinet-Le Pecq – La Varenne, all stations except Nanterre-Préfecture, Vincennes and Fontenay.
Evening Peak
Every 10 minutes:
Cergy – Noisy-le-Grand, all stations except Maisons-Laffitte and Houilles.
Poissy – Chessy, all stations except Sartrouville, Bry, Noisiel and Lognes.
St-Germain – Boissy, all stations except Nanterre-Ville and Nanterre-Préfecture.
Le Vésinet-Le Pecq – La Varenne, all stations except Vésinet-Centre and Chatou-Croissy.
La Défense – Torcy, all stations except Neuilly-Plaisance and Bry.
Chessy – Poissy, all stations except Bry and Neuilly-Plaisance.
Boissy – Le Vésinet-Le Pecq, all stations.
Noisy – Cergy-le-Haut, all stations except Houilles and Maisons-Laffitte.
La Varenne – St-Germain, all stations except Fontenay, Vincennes, Nanterre-Préfecture, Chatou-Croissy and Le Vésinet-Centre.
Off Peak
In both directions every 10 minutes:
St-Germain-en-Laye – Boissy-St-Léger.
Cergy-le-Haut – Marne la Vallée-Chessy.
In both directions every 20 minutes:
Poissy – Noisy-le-Grand - Mont d'Est.
La Défense – Noisy-le-Grand - Mont d'Est.
Off-peak, a train is scheduled every 3 minutes 20 seconds between La Défense and Vincennes in both directions.
