Overnight trains have made a real comeback across Europe as more routes reopen, and for budget travelers they solve two problems at once: a long-distance travel day and a night's accommodation, combined into one ticket.
What a budget berth actually looks like
A "couchette" is a shared compartment with 4–6 bunks, basic and functional rather than luxurious, and the budget option on most routes at $30–70. A private sleeper compartment costs considerably more and generally isn't necessary unless privacy matters more to you than the savings.
What to actually pack for the ride
Earplugs and an eye mask are close to mandatory — couchette cars are noisy at stops and lit by corridor light. Bring your own snacks and water, since dining options are limited or absent on most overnight routes. A padlock for your bag is a smart precaution in shared compartments.
Booking timing matters more here than for day trains
Popular overnight routes (Vienna–Venice, Paris–Nice-style routes, and similar) can sell out their cheapest berths 4–8 weeks ahead in peak season. Book earlier than you would for a daytime regional train.
Takeaway: A couchette berth booked several weeks ahead usually beats a budget flight plus a hotel night on total cost and hassle combined — treat it as a real transport option, not a novelty.