Dean Europe with a Global Eurail Pass can be one of the most rewarding experiences of your life. You get to see the countryside in a way that you never would driving a car. You also don't have to deal with the stress of navigation, breakdowns, refueling and parking. Instead of spending a 6 Hour Dr. just looking at the road you can spend six hours looking out the window of a comfortable train coach and actually take the scenery in. The entire experience can be dampened a bit if you happen to pack far too much. The ability to travel light will make your train vacation much more pleasant and make sure that you don't stress out during a time when you should be relaxing. Remember, you want to travel light but still keep room for all the souvenirs you're going to have to bring back with you as well.
The first thing that you absolutely need to have is your documents. Because you are traveling on a year else asks you will need to carry your passport with you at all times. When the person who checked tickets comes around to you, you must be able to provide both a Europe rail pass and the matching passport that goes along with it. This isn't to keep tabs on you as a traveler but to make sure that nobody else is using your Eurail Global Pass. Granted, because you are traveling over international orders regularly, TV passports is a good thing to have but you will find that the checks are almost always because of tickets and not because of customs.
The next most important thing I like to make sure that I have in my bag is my insurance information. I always purchase travel insurance before I go on a vacation because they don't want to have to die because I didn't spend 50 jocks on foreign health care. If you have any health problems it is incredibly important to let people know through documentation readily available on your persons so that if you pass out and can't tell them about your conditions they can probably figure it out themselves.
Another thing to check up on before you leave is whether or not you will need a visa to travel in whichever country it is you may be visiting. Depending on where you're from, some European countries require that you carried a visa with you at all times.
There are other forms of documentation that are very important to a European rail trip. When you buy your Eurail global pass it should come with a schedule, a traveler's guide, and a map of the European rail system. I found all three of these incredibly helpful for planning out my trip and figuring out which trains I could get on, which trains I couldn't in which trains require reservations prior to boarding. There are other guidance for traveling Europe by rail and although I can't attest to their quality, the free ones that came with my Eurail paths were plenty helpful and I would not have left home without them.
Some other things you are going to need for your trip are medical necessities and hygiene equipment. Just like any other trip you want to forget any bills you have to take or toothbrushes you may need to brush your teeth with. If you need glasses or contact lenses, make sure that you don't forget them on the counter before you leave your house. I ended up using my mini first aid kit quite a bit during my six month stay in Europe and would recommend taking something rather small because you don't want to take up too much space that you want to be there when you need it. I didn't shave every day that I kept a beard trimmer with me because it was much more convenient than finding a bathroom to shave my chin all every few days.
When packing clothing for your trip, make sure that you take into account your destination and the time to hear that you'll be traveling there. Big sweaters and jackets are basically useless year-round anywhere near so try and pack small sweaters and waterproof jackets so you can layer your clothing to keep warm rather than carrying one gigantic jacket around with you. I found that some dreams were unbearably hot and some unbearably cold so this layering technique made it really easy to change my wardrobe based on how I felt. I also had a little rain jacket for my backpack because a few times I ended up getting off a train in waiting outside in a downpour for my transportation to the hotel. This little jacket for my backpack made it incredibly easy to keep all of its contents dry and was a huge blessing. Plus, it made my backpack looks all that much cooler.
Some train rides along. Keeping yourself entertained isn't always as simple as just looking at the window so try and bring music, video games or books in the smallest forms you possibly can. If you are bringing your iPhone, put the music on it that you think you would like to listen to almost any movie that might keep you entertained. If you have an e-book reader, bring that rather than three or four books with you because they really do take up a lot of space.
For the most part, you have a power transformer on any of your electrical equipment they will be able to take in a 220 V European blood. They won't, however, be able to plug directly into the wall and for that you'll need an adapter. Make sure that you read the voltage allowances on the back of your products transformer to see if it can take the 220 V power supply. If not, there are products that will change the voltage down to a 110 V North American standard. If you have any electronics that require this, I suggest you pick one up before you go because they are rather expensive at tourist spots.
If you can find a small space to pack an umbrella, make sure that you do it. Although it's not the end of the world if you get what, it is really much nicer arriving at your hotel dry and not having to hang your clothes over the radiator overnight. Sunglasses are also another thing that you don't want to forget but it isn't the end of the world if you do because you can pick up a new pair when you're there.
A camera and cell phone are absolute must for any European vacation. You are going to have the images in your head forever but you might as well be able to show other people what you saw as well. Take as many pictures as you can and don't worry about looking like a tourist because you already do. Keep your cell phone on airplane mode if it hasn't so as to not get charged ridiculous roaming fees but it is incredibly important to have just in case there is an emergency. You don't want to be spending the night at a train station because you can't contact your transportation to the hotel or hostel.
Don't stress too much about what to bring on your trip because Europe is the same as North America in that they sell basically everything. If you forget it, you can buy it there. Remember, don't stress because this is supposed to be a vacation. Take it easy and you will have a fantastic time.