The overnight leg is one of the genuine efficiencies of long travel: you cover 600km, you sleep, and you save a hotel night. It is also one of the reliable ways to arrive somewhere at 5am, wrecked, with nowhere to go until 2pm.
Whether it works comes down to a handful of specifics.
The arithmetic, honestly
In favour: one hotel night saved, one day of travel avoided, and arriving at the start of a day rather than the end of one.
Against: you sleep badly, so the following day is at maybe 60 per cent. You arrive before check-in. And you cannot easily change plans mid-journey.
The rule that holds up: an overnight is worth it when the journey is over about ten hours and the alternative is a full day of daylight travel. Under that, take the day service and get a room.
Also worth counting: if you take three overnights in a fortnight, you will feel it in week two.
Night trains
Europe’s night trains largely died in the 2000s and have come back — ÖBB’s Nightjet network, Sweden’s services to the Arctic, the Caledonian Sleeper, Spain’s and Italy’s domestic routes.
The classes matter and the names are confusing.
Seats are the cheapest and are a night in a chair. Fine at twenty, poor at forty.
Couchettes are simple bunks, four or six to a compartment, mixed unless you book a female-only one. Sheets and a blanket are provided; there is no privacy and you sleep in your clothes.
Sleepers are proper compartments with one to three berths, a washbasin, and sometimes an en suite. Considerably more expensive and the difference between arriving rested and not.
For a first night train, a couchette in a four-berth is the value option; a two-berth sleeper is the one worth paying for if the following day matters.
In Asia, India’s 2AC and 3AC air-conditioned sleeper classes are the ones foreign visitors want — clean, curtained, with bedding provided. Sleeper class without air conditioning is fine by day and a long night otherwise. Book on IRCTC as far ahead as you can; popular routes sell out weeks out.
Vietnam’s Reunification Express soft sleeper, China’s high-speed sleepers and Thailand’s overnight services to Chiang Mai and the south are all genuinely comfortable.
Sleeper buses
Common in Southeast Asia and South America, and the two regions do it very differently.
South American premium buses — cama and semi-cama in Argentina, Chile and Peru — have seats that recline to 160 or 180 degrees, meals, and are a legitimately comfortable way to cross a continent. They are the best long-distance buses in the world.
Southeast Asian sleeper buses have flat pods designed for people around 165cm. If you are taller than that, you will be diagonal all night. They are cheap, they run everywhere, and they are a different proposition.
What to check before booking a bus: the operator’s reputation on that specific route, whether it is a direct service or one that changes at 3am, and whether the “VIP” designation means anything on that route or is just printed on the ticket.
Sleeping, practically
Earplugs and an eye mask. The single highest-value fifty pence in travel.
A layer. Both trains and buses run air conditioning at temperatures that make no sense, and it is always colder at 4am.
Something for your neck if you are in a seat.
Downloaded entertainment, because there will be no signal for hours.
Water and food. Buses stop at places of variable quality; trains in India and China have catering, most others do not.
Do not drink much before boarding. Toilets on overnight services range from adequate to memorable.
Safety
Overnight travel is generally safe, and the risks are specific.
Bags. Keep your valuables — passport, cards, phone — physically on you while you sleep, not in the overhead rack. A small bag used as a pillow is the standard solution. On trains, a cable lock through the strap and around the seat frame or luggage rack.
Arrivals. The genuine hazard is not the journey, it is arriving at 4am in an unfamiliar city. If you can, choose services that arrive after dawn. If you cannot, book accommodation for the night before as well so you can go straight there, or wait inside the station until it is light. This is worth the extra night’s cost.
Solo travellers can request single-sex compartments on most European night trains and on Indian railways.
Drink spiking on overnight buses has been reported on specific routes in a handful of countries. Do not accept food or drink from strangers on these services, which is a rule that sounds paranoid and is locally well known where it applies.
Where the overnight is a false economy
Short countries. A six-hour overnight means being woken at 4am.
When you arrive somewhere with nothing open, no left luggage, and eight hours before check-in.
Two nights running. Whatever you save, you spend the following two days recovering.
When the day version is spectacular. The Cusco–Puno route, the Belgrade–Bar line, the Hue–Da Nang coast, the Glacier Express: taking these overnight saves a hotel and costs you the reason to be on that train.