If you spend a few extra dollars, you can reserve an overnight couchette bunk. Taking long train trips at night makes sense. Every night spent on the train gives you an extra day to sightsee, saves you the cost of a hotel, and allows you to arrive early before the cheaper hotels fill up. The scenery missed is usually insignificant when you consider the time you gain.

There are different ways to travel overnight on a train. You can sleep in your seat, or rent a couchette or get yourself a sleeper. Whether you have a ticket or a railpass, you must pay extra for a couchette or sleeper.

Sleeping in your seat: If you're in an open-style car (with airline-type seats) or in a crowded compartment, you'll sit up miserably all night. But if the compartment is not crowded, then you may be able to pull out the seats to make a bed.

Couchette or berth: One of Europe's great bargains is the $25 couchette. It's a bed in a usually lockable compartment with two triple bunks (with a blanket, pillow, clean linen, and up to five co-ed compartment mates). As you board, you'll give the attendant your couchette voucher, railpass or ticket, and passport. He deals with conductors, thieves, and customs officials on your behalf as you sleep uninterrupted in relative safety.

Book your couchette several days in advance, either through a European travel agent or at train stations.

Sleeper: A sleeper offers more privacy and comfort than a couchette. You'll pay from $40 to $100 on top of your ticket price for a berth in a still-crowded one-, two-, or three-bed sleeper with a tiny sink.

Editor's note: Get Eurail passes at the cheapest source of rail passes online: Rail Pass and Rail Europe