RATP trains to Robinson and Saint-Rémy-lès-Chevreuse make end-to-end ("bout à bout") connections with SNCF trains to Aulnay-sous-Bois, Paris-Charles de Gaulle Airport and Mitry, 42 kilometers , but without through working due to a difference in electrical system (1500 V DC to the south, 25 kV AC to the north).