Take the train from Interlaken West to Wengen with a change of train at Lauterbrunne. Departures are every 45 minutes from 6:30am to 11pm, costing 16F one-way. After a stopover at Wengen, the train goes on to Kleine Scheidegg and Jungfraujoch. For rail information, call tel. 0900/300-300.
If you're driving, head south from Interlaken toward Wilderswil, following the minor signposted road to Lauterbrunnen, where you'll find garages and open-air spaces for parking. You cannot drive to Wengen -- you must take the train. You can park in one of the garages at Lauterbrunnen for 12F to 18F a day. Trains from Lauterbrunnen to Wengen leave at the rate of one every 15 minutes from 6am to midnight, costing 7F one-way.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.