There are trains from the station outside Le Chene Gris, well certainly when we were there as the camp pitch we had was the other side of the fence! Double decker trains! From memory the line is a branch line with the end of the line not too far away. Would be possible to use to go to Disney I believe but would require a change at Tournan en Brie which is the other end of the line and would take you far longer than driving! Fine if you don't have a car I guess but how long the trains run into the evening I couldn't tell you!