A night train, or overnight train, is just that - a train that departs Point A in the late evening and arrives at Point B in the early morning.
Given the rise of budget airlines and high-speed trains in Europe, traveling by overnight train might seem a bit antiquated. For some destinations, however, taking an overnight train can be a cost-effective way to travel—especially since it includes what you would normally be spending on a hotel room.
Overnight trains often have regular seating, but for maximum comfort we recommend booking either a couchette or a sleeper compartment. These come in different variations, depending on how many bunks you need and whether you want an entire compartment to yourself, and sometimes come in both first- and second-class options.
Sleeper compartments are usually the nicer option—some of them even come with en-suite wash basins and private bathrooms. Couchettes tend to be the most economical choice, with 4-6 bunks per compartment, but are not always segregated by gender. Bed linens, blankets, and towels are provided in almost all sleeper and couchette compartments.
Unless you're traveling alone and booking an entire compartment for yourself, there will typically be regular train seats in the cabin when you board. These can be made into another bunk for sleeping.