It is not possible to travel with a Carte Orange beyond the zones that the card is valid, and the transportation authority requires the travelers to purchase a ticket valid for the entire trip, regardless of the zones already covered by the carte orange. While some stations have special ticket windows that sell extensions for arriving passengers who need them (notably for tourists the Versailles station in Zone 4), others do not. This sometimes results in a traveller being stuck in the station until they can attract the attention of a metro employee, or jump the turnstile. The Charles de Gaulle Airport RER stop (located in Zone 5) is, unfortunately for tourists, one of those stations that does not have an accessible ticket window on the incoming side.