Using a rail pass from the CDG to Paris

Bump. I'm not a rail pass guy, but I bet it won't work. RER B to A will work. The change will be at what's billed as the largest underground station in the world, but your two platforms will be close together. The tickets will stiff you about nine euro per person each way. It's going to take real close to an hour each way.

Thanks for the bump, Ed. I saw the message but didn't have time at the time. Please excuse me for doing this off the top of my head tonight, so there may be a station or two off. It is confusing using the RER with passes. It is confusing because only part of the RER is covered. The heavy rail in France, the TGV, the CoRail, the TER, the suburban SNCF, Eurostar, and parts of the RER are operated by SNCF, the French national railway - and on those (ok, not Eurostar because it is a special case like Thalys) operated by the SNCF the pass works. May have to get a seat reservation on some, but it works. Other parts of the RER are not operated by the SNCF but RATP, the Paris Métro and bus operators. On bits of the RER operated by the RATP the passes are NOT VALID. So, which parts are which? It is confusing. My information is that the following parts of the RER are where passes are valid : RER Line A – SNCF from Nanterre Préfecture to Possy or Cergy-le-Haut RER Line B – SNCF from Gare du Nord to Aéroport Charles de Gaulle or MitryClaye. RER Line C – SNCF in its entirety. RER Line D – SNCF in its entirety except between Gare du Nord and Chatelet les Halles. RER Line E – SNCF in its entirety. If you have passes and wish to use these routes, you should request a Contremarque de Passage from the SNCF ticket office at the start of your journey. This
will give you access through the automatic ticket barriers. You really do need to be careful. I travel with staff passes with the same rules. I put my passes in my pocket in Paris and use my little packs of Métro tickets. Good luck...