Eurail Pass: How do you make seat reservation if you are already in Europe?

Using a ticket window should not be a problem even in small towns. Just write what you want very clearly on paper -- dates, times, point a to b, and add the French words for Seat Reservation. Show the pass and the ticket agent will figure it out. Second, technically you are paying a train premium to ride certain trains and they give you a seat reservation so we often call it a seat reservation when really it is a premium fee. Therefore, you can still get in trouble if you get on a train requiring a premium and you have not paid it. Not familiar enough with the Frence/Swiss rail system but I would assume that all of the high speed trains and some of the lesser train would require the premium.

can we just show up and hop on a train Yup Trains traveling within Switzerland, with the exception of some private scenic trains, neither offer nor require reservations. I see that you will be on a portion of the Golden Pass, between Interlaken and Luzern. That is, if you take the extremely scenic narrow gauge rack railway Zentralbahn train over the Brünig Pass. There are frequent trains over that route which are not Golden Pass branded but go the same way over the same track at the same speed for a fraction of the money, and with no reservations. There is a fast train over a longer route via Bern and Olten which often uses double decker trains but not nearly as scenic. Be aware that you don't need "Ost" in all caps. It just means "east". Interlaken has a West and an Ost station.

I would assume that all of the high speed trains and some of the lesser train would require the premium. Not so in Switzerland. You can hop on and off TGVs, DB ICEs, and (in the past) CisAlpino, all day without reservations in First or 2nd Class trains within the borders of Switzerland. It is true that if you want to cross the border with TGV trains you need a seat reservation. ICE trains don't require (but do offer) seat reservations going into Germany. The only trains in Switzerland requiring reservations are the tourist trains on the scenic lines (predominantly catering to First Class rich tourists who want the tilting wine glass, air conditioning, panoramic windows). Each of those routes also have frequent non reserved trains doint the same thing with windows which go down so you can see, photograph without reflection, and allow the gorgeous Swiss scenery enter your ears, nose, and eyes.

Thanks for the info everyone. A few more questions: 1. So we're not at risk of having a train full at this time of year? 2. Procedure wise, if we are hoping on a train, do we just (a) fill out the date slot on our eurail flexipass with the current date, then (b) hop on any coach/car and find 2 seats? How do we know seats aren't reserved already to other passengers?

I just returned from Switzerland and had no troubles with getting a seat on their national line (sbb). The only time you'd need a reservation is on the private lines like Glacier Express (from my experience).

Full trains would be unlikely this time of year. Write in the date, in pen, prior to boarding the train. If the date's not filled in when the conductor arrives to check tickets, you'll be fined. Reserved seats will have a card or electronic notice above the seats (where the luggage rack is). Some seats are reserved for part of a journey only and you can sit there when it's free. If you do happen to accidently sit in a reserved seat, you'll be asked to move, no biggie.

Thanks Jennifer! You were dead on. Train were very sparsely filled so getting a seat on all the trains so far through Berner Oberland was without a problem.