Which RER Train Do I Take? Paris RER Branches and Codes
Which RER Train Do I Take? Paris RER Branches and Codes
In short. On the Paris RER (lines A to E), the line letter and the direction are not enough: almost every line splits into branches, and on the same branch some trains stop everywhere while others skip stations. To board the right train, check three things: the terminus shown on the train and the screens, the platform screen that lights up or lists the stations the train serves, and at big SNCF stations the platform number ("voie"), which sometimes appears only a few minutes before departure. Each train also has a four-letter mission code (like ZEUS or NORA) whose first letter usually stands for its destination. Zeppelin Map, the iOS transit navigation app for Paris developed by Anaximae SASU, shows you only the trains that actually stop at your destination, with their live times and the platform as soon as it's announced.
The metro is forgiving. Get the line and the direction right and every train stops at every station. The RER is not like that. You can be on the right line, on the right platform, facing the right direction, and still take a train that flies past your station or turns off toward a different suburb.
It happens to Parisians too, usually once. This guide is so it doesn't happen to you.
Why can't I just take the first RER train in my direction?
Because the RER is a network of regional railways that cross Paris underground and then split into branches in the suburbs. The central part is shared; after that, trains go different ways. On top of that, some trains are omnibus (stopping everywhere) and others are semi-direct or direct, skipping stations to go faster.
So "RER A toward the east" can mean a train to Boissy-Saint-Léger or a train to Marne-la-Vallée – Chessy. They share the track through Paris, then part ways. If you're going to Disneyland and you board the Boissy train, you'll notice when the stations start to look unfamiliar.
Where do the RER branches go?
A quick map in words, with the destinations visitors actually need:
RER A: west to Saint-Germain-en-Laye, Cergy-le-Haut or Poissy (Rueil-Malmaison for the Malmaison château is on the Saint-Germain branch); east to Boissy-Saint-Léger or Marne-la-Vallée – Chessy (Disneyland Paris). La Défense is on the shared section.
RER B: north to Aéroport Charles de Gaulle or Mitry-Claye; south to Robinson or Saint-Rémy-lès-Chevreuse. Gare du Nord, Châtelet, Saint-Michel, Luxembourg and Denfert-Rochereau are on the shared section.
RER C: the most branched line. For the palace, you want Versailles Château Rive Gauche, not Versailles Chantiers (which works, but leaves you a longer walk). Other branches go to Pontoise, Saint-Quentin-en-Yvelines, Massy-Palaiseau, Dourdan and Saint-Martin-d'Étampes. Along the Seine it serves the Eiffel Tower (Champ de Mars – Tour Eiffel), Invalides, Musée d'Orsay and Bibliothèque François Mitterrand.
RER D: north to Creil or Orry-la-Ville via the Stade de France; south to Melun, Malesherbes or Corbeil-Essonnes.
RER E: from Haussmann – Saint-Lazare east to Chelles-Gournay or Tournan; west via a new tunnel to La Défense and Nanterre – La Folie since 2024, with the extension to Mantes-la-Jolie scheduled for 28 February 2027.
The rule is the same everywhere: before boarding, find your station on the screen and make sure this particular train stops there.
How do RER platform screens show which stations a train stops at?
On most RER platforms there are screens listing the next trains with their terminus and their departure time, and a display of the line where the stations served by the next train are lit (or listed), while the ones it skips stay dark or are missing. Newer screens show the full list of stops for each train.
The method takes ten seconds:
Look at the next train: its terminus and its departure time.
Find your station in the list or on the lit-up line.
If it's lit or listed, board. If not, wait for the next one and check again.
Inside newer trains, screens show the next stops too, which is reassuring once you've boarded, but the moment to check is before the doors close.
What do the four-letter RER codes mean?
Every RER train has a mission code: four capital letters shown on the front of the train and on the platform screens, like ZEUS, NORA or COHI. They help railway staff and regular commuters recognize a service at a glance.
How they work, roughly:
The first letter is usually the initial of the destination. On RER A, for example, codes starting with Q go to Marne-la-Vallée – Chessy.
The second letter often hints at the type of service: on several lines "O" means omnibus.
The last two letters vary by line: sometimes they encode the route, sometimes they're just chosen to make a pronounceable word (since 2022 on RER C, names like ROMI, SARA, NORA or LARA). On RER A and B, two digits are added for the direction.
Honestly, you don't need to decode them. What's useful is this: if your app or a timetable tells you the code of your train, you can spot it on a busy screen in a second. And if you're on a platform and none of the next trains carries the code you expected, you might be on the wrong platform.
How do I find the right platform ("voie") at a big Paris train station?
In the underground RER stations in central Paris, each direction has its own platform, and the signs say which branches it serves. In the big surface stations (Saint-Lazare, Gare du Nord, Gare de l'Est, Gare de Lyon, Gare Montparnasse, Gare d'Austerlitz), suburban trains (Transilien and some RER) leave from numbered tracks called voies, and the track is often displayed on the departure board only a few minutes before departure.
What locals do: they stand in the middle of the concourse, in front of the big departure board, find their train by time and destination (and code), and wait for the "Voie" column to fill in. Then they walk, fast. If you see a crowd suddenly moving all together, that's usually the moment the track number appeared.
A practical tip: allow a few extra minutes at these stations. The walk from the board to the end of a long platform can easily take three or four minutes with luggage.
Do I need a different ticket for the RER?
Inside Paris, the RER works with the same tickets as the metro. Outside Paris, the Métro-Train-RER ticket covers the whole Île-de-France region, except the airports: for Charles de Gaulle (RER B) and Orly you need the dedicated airport ticket or a pass that includes the airports. Disneyland (RER A) and Versailles (RER C) are covered by the standard Métro-Train-RER ticket. Our Paris metro tickets guide has all the prices.
Which trains go to Disneyland, Versailles and the airport?
The three questions every visitor asks:
Disneyland Paris: RER A, east, trains to Marne-la-Vallée – Chessy. Not Boissy-Saint-Léger. The station is right at the park entrance.
Palace of Versailles: RER C, west, trains to Versailles Château Rive Gauche. The RER C sometimes has closures of its central section for works, especially in summer; on those days, check alternative routes (Transilien trains from Saint-Lazare or Montparnasse also go to Versailles).
Charles de Gaulle Airport: RER B, north, trains to Aéroport Charles de Gaulle 2 TGV (stopping at Terminal 1 first). Not Mitry-Claye. Some trains skip stations between Paris and the airport, others stop everywhere; both get you there.
How does Zeppelin Map pick the right RER train for you?
This is where an app really earns its place, because the information exists but it's spread over three screens and a timetable. Zeppelin Map (the iOS transit navigation app for Paris, developed by Anaximae SASU) does the filtering for you:
Only the trains that stop at your destination. For RER and Transilien legs, the list of next departures shows the trains that actually serve the station you're going to, so the Boissy train doesn't show up when you're headed to Disneyland.
Live times and the platform. Departure times update in real time, cancelled trains disappear, and at the stations where the information is published, the app shows the platform ("voie") as soon as it's announced. If the train is about to leave and the platform still isn't published, the app tells you to check the station's board instead of guessing.
The right car, for part of RER A and B: where RATP's open data covers it, the app tells you which car to board so you're already in front of the stairs for your transfer or exit.
The full day, not just one train. With Bibomap™, the app's multi-stop planner, you add Versailles, a lunch stop and an evening museum, and the app orders them and connects them with metro, RER, bus, tram or walking.
For metro, bus and tram legs, the app also shows the next departures in real time, so you know at a glance whether it's worth hurrying.
FAQ — Frequently Asked Questions about the Paris RER
How do I know if an RER train stops at my station?
Check the platform screens before boarding: they list the next trains and light up or list the stations each one serves. If your station isn't shown for the next train, wait for the following one. Zeppelin Map shows only the trains that actually stop at your destination.
What do the four letters on RER trains mean?
They're the mission code of the train. The first letter usually stands for the destination (on RER A, codes starting with Q go to Marne-la-Vallée – Chessy), the second often indicates the type of service, and the last letters vary by line. You don't need to decode them, but they help you spot your train on a screen.
Which RER goes to Disneyland Paris?
RER A, eastbound, trains to Marne-la-Vallée – Chessy. The other eastern branch goes to Boissy-Saint-Léger, so check the terminus before boarding.
Which RER goes to the Palace of Versailles?
RER C, westbound, trains to Versailles Château Rive Gauche, the closest station to the palace. Check for works on the RER C before you go, especially in summer.
Which RER goes to Charles de Gaulle Airport?
RER B, northbound, trains to Aéroport Charles de Gaulle 2 TGV, which also stop at Terminal 1. The other northern branch goes to Mitry-Claye. You need the dedicated airport ticket or a pass that includes the airports.
Why is the platform not shown yet at Gare Saint-Lazare or Gare du Nord?
At big surface stations, suburban trains leave from numbered tracks ("voies") that are often displayed only a few minutes before departure. Wait in front of the main departure board and allow a few minutes to walk to the platform.
