t To save some travel days or time on a Flexi Eurailpass, or time on an unlimited pass, don’t validate your pass until you are ready to really start traveling. For example, if you fly into Madrid, and then intend to go to Pamplona to run with the bulls for a week or so, it is worth buying a ticket from Madrid to Pamplona (for about USD 35), rather than starting up your unlimited pass, or starting up and using a day on a Flexi pass. Try to plan any long city stays on either end of your trip, for the same reason. If you want to spend two weeks in Paris, don’t do it in the middle of your trip while your pass is activated. Balance this, though, with the possible need to take a break mid-trip. If you aren’t enjoying your trip because of too much go-go-go, don’t keep pushing simply to “get the most” out of a pass.

- Don’t forget that even though a Flexi pass works off travel days used, it too has a one- or two-month clock ticking, just like an unlimited pass.

- When taking a night train, if you leave after 7pm (1900) you will only be charged one Flexi Eurailpass day, for travel up to midnight on the next day (29 hours later). You can cover a lot of ground in 29 hours. Just remember to enter the next day’s date on your Flexi pass or you’ll be charged for two days.

- Most night trains do indeed leave after 7pm. Once, though, I had to take a night train from Oostende that left at about 6.15pm, so I bought a USD 10 ticket to Ghent, where the train arrived just after 7pm. From Ghent onward I used my pass, and only had to use one day to get all the way from Ghent to Copenhagen. The conductors nodded their heads in admiration at this bit of chicanery, and labeled me the “Clever American.”