Plan on spending the better part of your day on the train when you book travel from Interlaken to Venice. With brief station stops included, the trip averages about 9.5 hours.
Begin your train travel at Interlaken Ost (East). Although there are two train stations in Interlaken (Ost and West), Interlaken Ost offers the most convenient and frequent international service.
Expect to make one or two connections along the route. The most common route from Interlaken to Venice is through stations in Lucerne (Luzern) and Milan (Milano Centrale).
Arrive at Venezia S Lucia, the final stop along the route to Venice.
To book your ticket, contact Eurail at 1-866-638-7245 or visit their Web site (see Resources, below). Click on 'Train Tickets and Schedules,' visible on the left-hand menu. You'll then enter your trip details, including travel dates and the number and age of passengers.
Choose a ticket option that offers a la carte food service if you want more than what would be available in the bar-buffet car. Each train along the Interlaken to Venice route has a la carte food service in first class and above.
Book travel in different classes from stop to stop if you feel you need to adjust your comfort level. Second and economy class is fine for the trip to Luzern, but the longer route to Centrale Milano might be more comfortable in first class.
Rely on Visa or MasterCard when you purchase your train travel. They're the most commonly accepted credit cards, and you're likely to run into the least amount of problems using them online or other the phone.