Book tickets on the Eurail website. Tickets from Zurich to Frankfurt will cost anywhere between $150 and $300 depending on which train class you wish to travel. Second class is the most affordable and is adequate for shorter trips and this trip is fairly short. First class gives you bigger seats, meals and better service.
Consider a Eurail Germany-Switzerland Pass, which will save you money if you plan to travel between Zurich and Frankfurt on multiple occasions. This first-class Railpass allows unlimited train travel during 5, 6, 8 or 10 days within a 2-month period. Keep in mind that if you book a child's Eurail Germany-Switzerland Pass, it will cost about 50 percent less.
Book a Eurail Germany-Switzerland Saverpass if you are traveling with a group. You'll save about 20 percent when compared to a standard Railpass.
Book a Eurail Germany-Switzerland Youth Pass for second-class travel if you are under 26. Prices vary according to how many days you expect to travel (5, 6, 8 or 10).
Learn a little German. German is Switzerland's most common language (French is also prevalent) and the official language of Germany. Most Europeans know some English and many are fluent, but it is always a good idea to learn some key German words like 'bathroom.'
Allow for your trip between Zurich and Frankfurt to take around 4 hours. There are nonstop trips between the 2 cities as well as trips that go through Stuttgart and Basel.
