The Eurail Pass provides a significant discount for the journey to the Jungfraujoch, often referred to as the "Top of Europe," but it does not cover the entire trip for free. Specifically, your Eurail Pass is fully valid on the trains as far as Interlaken. From Interlaken onwards—traveling toward Lauterbrunnen or Grindelwald and then up to the Eiger Gletscher and the Jungfraujoch—the lines are operated by the Jungfrau Railway, which is a private company. Holders of a Eurail Pass typically receive a 25% discount on the ticket price for this final, most expensive leg of the journey. It is important to note that even with the discount, the ticket can be quite costly due to the incredible engineering required to maintain a railway at 3,454 meters. You do not need to use a "travel day" on your Eurail Pass to get the 25% discount; you simply need to show your valid pass at the ticket counter. However, if you want the train from your starting city to Interlaken to be covered, that will count as a travel day. Many travelers find that the Swiss Travel Pass offers better coverage for this specific region, so comparing the two based on your itinerary is a smart move before you arrive in the Alps.