Bon jour. I'll be visiting Paris (my first time in town) for work in July, and since I'll be staying a little less than a week (arriving on a Tuesday) I was planning to purchase a Navigo Découverte weekly pass. I'll be working in the center of town but staying in Rambouillet, which leads to my question. When I check commuting possibilities from Rambouillet to Gare Montparnasse, I see two different types of trains--Transilien line N and TER. The most obvious practical difference between the two is travel time, a factor of the disparity in number of stops. In researching multiple official sites, I cannot see a definitive pronouncement as to whether or not the TER trains (with numbers like 862421) within zones 1-5 are covered by the Navigo Découverte weekly pass for those zones. If not, the N trains are the obvious option, but I wanted to make sure. Thanks in advance.
It's not very clear what is covered by Navigo, but yes the Navigo Découverte covers Ter trains within Ile-de-France's (IdF) zones 1-5.
Rambouillet is in IdF zone 5 (see this page for a Paris train zone map). Zone 5 is covered by Navigo. Any part of Ter train lines outside / beyond zone 5 (further away from central Paris) require a separate pass with Hauts-de-France (HdF) coverage. This Ter page (in French) describes the use of various HdF passes covering Ter trains outside of IdF zone 1-5 and how they combine with a Navigo pass for coverage inside zones 1-5 as some Ter lines operate continuously over both these territories.
This Navigo Week pass page (in French) for Ile-de-France Mobilités also discusses (in the Conditions section) that Navigo covers:
- À l’intérieur des zones de validité, le forfait Navigo Semaine est valable sur tous les modes de transport (métro, train, RER, tram express, tram, bus y compris Filéo), à l’exception de certaines dessertes directes d’aéroports (Orlyval, Bus Direct Paris-Aéroport ex-Cars Air France, navettes VEA Disney) et des bus touristiques (OpenTour, Cars Rouges)."
Translated that says:
Inside the zone coverage area, the Navigo Weekly pass is valid for all transport methods ([Paris] Métro, trains, RER, express trams, trams, buses including Filéo [brand buses]), except certain direct lines to airports (Orlyval, Air France coaches, Disneyland Paris shuttles) and tourist buses (OpenTour, Car Rouges).
The key method listed there is "trains". Which is understandably/unfortunately vague, but covers all SNCF trains (of various branding) which use unreserved-seating such as Transilien and Ter.
Hope this helps.