The key is to buy the narrowest pass that will get you where you want to go. For multinational travel within Europe, the Eurail pass is best. It includes 17 countries in Western Europe and, Hungary and entitles you to free or discounted travel on some suburban trains, private railways, national buses and even some ferries and excursion boats. The Eurail Saver pass requires different numbers of travelers during winter and summer, but gives special discounts to seniors and students. As with hotels, trains offer a brochure with room layouts.
Accommodations vary widely for each train.
West of the Mississippi, there are larger accommodations available, including a family bedroom. Before you select your berth or seat, know the location of the bathroom and don't take a seat or room nearby. If you have a pull-down bed, be sure that you can get to the toilet in the room without putting the bed back up. Bringing blankets, pillows and extension cords is up to you. Fussy sleepers will need them.