Departing from Paris, it’s easy to reach key locales in this region by rail because you can take advantage of the SNCF’s main-line and Transilien networks, as well as RER routes, which are part of Paris’s comprehensive RATP public transit system. Chartres and Chantilly, for example, are served by both main-line and Transilien trains; those bound for Chartres leave from Gare Montparnasse (50–70 minutes), while those going to Chantilly leave from Gare du Nord (25–30 minutes). Versailles is best accessed via the RER-C line, which gets you within a five-minute walk of the château (45 minutes); and the RER-A line deposits you 100 yards from the entrance to Disneyland (40 minutes). Note that the Parisian station you start from is typically determined by the direction you’re heading in.
SNCF. 3635; www.sncf.com.
Transilien. 3658; www.transilien.com.