Bonjour--

I have looked in a fairly old message thread
(http://www.fodors.com/forums/threadselect.jsp?fid=2) and on the RATP RER Ile de France plan and cannot figure out where RER C1 from Pontoise goes after it passes President Kennedy. Will all of the C routes pass through Gare d-Austerlitz from time to time, or is RER C1 always linked with a particular other C-endpoint like C5 or C7?

Also, if one has a Carte Orange for the central area (zones 1-2) will a RER ticket to Pontoise cost less than if you didn't have the C.O.?

Merci!

- Yes, all RER C routes will go through Gare d'Austerlitz. After the Avenue du Président Kennedy-Maison de Radio France station, the train will call at Champ de Mars Tour Eiffel, Pont de l'Alma, and so on ...

- A train starting at an odd endpoint will end at an even endpoint, and vice versa. (But this numbering of termini is quite confusing IMO).

- No, you can't buy a fare extension on the Paris transit system, so your O/D ticket Pontoise-Paris section urbaine will cost the same regardless your possession of a CO.

Merci, superheterodyne--

Your post answers my questions fully.

But let me see if I understand the broader RER route concept.

If I wanted to go from Pontoise (the C1 terminus) to Versailles, could I take any of the C trains and transfer to a C5 train at some place like Champs de Mar--Tour Eiffel?

And if I wanted to go somewhere on the C2, C4, C6, or C8 lines, I should wait for a train with the line designation I wanted leaving Pontoise?

You're welcome !

>> But let me see if I understand the broader RER route concept.

If I wanted to go from Pontoise (the C1 terminus) to Versailles, could I take any of the C trains and transfer to a C5 train at some place like Champs de Mar--Tour Eiffel? <<

Yes, exactly. You can also buy a through ticket for this route.

>> And if I wanted to go somewhere on the C2, C4, C6, or C8 lines, I should wait for a train with the line designation I wanted leaving Pontoise? <<

This is a little bit more tricky. You can't always reach all the odd termini from an even one (and vice versa), and if the line diagrams don't show it very clearly. The SNCF issued some time ago a transit map where all the routes were clearly and separately marked. This made very "thick" common trunks but was very informative, I think. Unfortunately it's been discontinued.

Trais departing from Pontoise will terminate either at Pont de Rungis/Massy-Palaiseau (C2), Brétigny (fork between C4 and C6) or Bibliothèque Francois Mitterand (intermediate terminus).

So, for example, it is impossible to reach the C8 terminus (Versailles Chantiers through Juvisy and Massy Palaiseau) directly from Pontoise.

You will find C8 - C5 "Versailles-Versailles through the loop trains".

Hope it's clear enough... the octopus-like RER C is quite complex to understand, let alone to operate !

Last but not least : the commontrunk between Invalides and Gare d'Austerlitz shuts down for 1 month in summer ... until 2017 ! This is due to major and much-needed renovation work.

Merci, superheterodyne, un deuxieme fois!

I guess if we want to do anything that might require a change of trains we will just ask how to do it at a ticket booth.

Oh, once you understand where to change trains - you just need to watch carefully at the displays on the platforms, which happen to be quite clear !