Here are some tips for train travel in various regions. Some of these tips I learned myself while travelling on board these trains, but some of them I learned from my favourite resource on worldwide train travel: The Man in Seat Sixty-One.

Vietnamese Long Distance Sleepers

• Buying tickets:
  Buy tickets online at baolau.com. Or, you can buy tickets at the departure railway station. If you have ordered your tickets online, there is no need to present a physical ticket for boarding. The booking website should email you an e-ticket with a QR code that you must present to the conductor when boarding.
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• Classes:
  Soft sleeper (4 beds/cabin, with door), and hard sleeper (6 beds/cabin, with door).
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• Ticket:
  Your ticket will contain your carriage number and your bed number. The tickets are in both English and Vietnamese.
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• Food and drink:
  Restaurant car, food carts, and hot water dispensers are available. Be sure to bring some snacks, just in case your trip begins after the restaurant car is already closed and the food carts have already stopped running.
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• Smoking:
  Smoking is allowed in the area in-between carriages.
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• Toilets:
  Toilets are available in each carriage, but there are no showers on board.
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• Charging:
  There are power outlets located either inside or outside your cabin. But, to be safe, make sure to pack along a fully charged portable charger.

Chinese Long Distance Sleepers

• Buying tickets:
  Buy tickets online at baolau.com or trip.com. Or, you can buy tickets at any Chinese railway station. When ordering online, collect your tickets from any railway station’s ticketing counter. Present your passport and the booking number (usually starts with an E) to the staff.
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• Classes:
  Soft sleeper (4 beds/cabin, with door), and hard sleeper (6 beds/cabin, without door). Hard sleepers are cheaper and equally as comfortable as soft sleepers if you don’t mind the lack of privacy. It is common for other passengers to sit on the lower bunks during the day, so make sure to share the space if you occupy the lower beds.
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• Ticket:
  Your ticket will contain your carriage (车, che) number and your bed (铺, pu) number. In hard sleeper cabins, there are 3 levels of beds: upper (上, shang), middle (中, zhong), and lower (下, xia). In soft sleeper cabins, there is no middle bed.
  Once on board the train, the conductor will exchange your ticket for a card. Be sure to exchange your card for your ticket again before you alight.
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• Food and drink:
  Restaurant car (餐车, can che), food carts, and hot water dispensers are available.
  Be sure to bring some snacks, just in case your trip begins after the restaurant car is already closed and the food carts have already stopped running.
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• Smoking:
  Smoking is allowed in the area in-between carriages.
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• Toilets:
  Toilets are available in each carriage, but there are no showers on board.
  Soft sleeper carriages usually have Western-style toilets, while hard sleeper carriages usually have squat toilets.
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• Charging:
  There are power outlets located either inside or outside your cabin. But, to be safe, make sure to pack along a fully charged portable charger.

Chinese High-Speed Rail

• Buying tickets:
  Buy tickets online at baolau.com or trip.com. Or, you can buy tickets at any Chinese railway station. When ordering online, collect your tickets from any railway station’s ticketing counter. Present your passport and the booking number (usually starts with an E) to the staff.
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• Classes:
  1st class, and 2nd class. As rides on the high-speed rail tend to be short, save money and opt for the 2nd class seats. In terms of comfort, 2nd class seats are on par with or better than economy class on airlines.
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• Ticket:
  Your ticket will contain your carriage (车, che) number and your seat number.
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• Food and drink:
  Food carts may operate on board.
  Be sure to bring some snacks, just in case food carts do not operate on your particular trip.
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• Smoking:
  Smoking is strictly not allowed on board.
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• Toilets:
  Western-style toilets are available in each carriage.
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• Charging:
  There are power outlets located below each seat.

Trans-Mongolian Long Distance Sleepers

• Buying tickets:
  Buy tickets at the departure railway station. The station are unlikely to speak English: so, do have the name of your destination, your desired class, and your desired timing written or translated into Mongolian beforehand.
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• Classes:
  Soft sleeper (4 beds/cabin, with door), and hard sleeper (6 beds/cabin, with door).
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• Ticket:
  Your ticket will contain your carriage (ВАГОН, vagon) number and your bed number.
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• Food and drink:
  I have not seen restaurant cars or food carts on board. But, there are hot water dispensers available. Make sure to bring along food, such as instant noodles, for your journey.
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• Smoking:
  Smoking is strictly not allowed on board.
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• Toilets:
  Toilets are available in each carriage, but there are no showers on board.
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• Charging:
  There are power outlets located either inside or outside your cabin. But, to be safe, make sure to pack along a fully charged portable charger.

Trans-Siberian Long Distance Sleepers

• Buying tickets:
  Buy tickets online at rzd.ru. When booking, if you see an “@“ symbol, it means that the journey allows boarding via e-ticket. You will receive an email containing an e-ticket. Just present this e-ticket to the attendant when boarding. If there is no “@“ symbol, you will need to present your booking confirmation to a ticketing counter at the departure station. Collect your tickets from the counter using your passport and booking confirmation, and use the physical ticket to board the train. Take note that as of the time of writing, all train timings listed are in Moscow time (UTC +3). However, this might change, so make sure you know whether your train is running on local or Moscow time.
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• Classes:
  There are 3 tiers of train services. Routes with single digit numbers (e.g 001) are the most expensive but generally run using newer and faster trains. Routes with double-digit numbers (e.g. 069) are more affordable and generally run with only slightly slower and less comfortable trains. Routes with 3 digit numbers (e.g 115) are the cheapest but generally run with the slowest and oldest trains. On each route, there are usually 3 classes of sleepers: 1st class sleeper (2 beds/cabin, with door), 2nd class sleeper (4 beds/cabin, with door), and 3rd class sleeper (6 beds/cabin, with door). It is common for other passengers to sit on the lower bunks during the day, so make sure to share the space if you occupy the lower beds.
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• Ticket:
  Your ticket will contain your carriage (ВАГОН, vagon) number and your bed number. Tickets are in both English and Russian.
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• Food and drink:
  Restaurant car (РЕСТОРАН, restoran), and hot water dispensers are available. There’s no need to pack along snacks as the train will make longer stops every few hours. Use these stops to buy snacks from the station minimarts. Just make sure you know what time your train will leave the station! Restaurant cars have menus in English. Ordering is simple: just place your order with the restaurant car attendant who is usually located at the ends of the restaurant car.
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• Smoking:
  Smoking is strictly not allowed on board. Every few hours, the train will make a longer stop at stations. You can use those stops to smoke on the platform.
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• Toilets:
  Toilets are available in each carriage, but there are no showers on board.
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• Charging:
  There are power outlets located either inside or outside your cabin. But, to be safe, make sure to pack along a fully charged portable charger.

European Eurail Trains

• Buying tickets:
  With a Eurail pass, you’ll only need a valid pass to board any train in your pass area. Do remember to follow the instructions in your pass regarding validity and filling in the travel diary. Also, do take note that some trains, especially international ones, will require a seat reservation which can cost extra.
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• Classes:
  Most trains consist of 1st Class and 2nd Class cabins. The Eurail Youth Pass allows access only to 2nd Class seats, and sitting in a 1st Class cabin on a Eurail Youth Pass can result in a fine: so, make sure you’re boarding and sit in the right cabin.
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• Ticket:
  No ticket is required to board participating Eurail trains unless the route requires a seat reservation.
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• Food and drink:
  Most trains run relatively short distances or are commuter trains, and as such, may not have a cafe car on board. However, some long-distance high-speed trains do have bistro cars on board, and some commuter trains do have onboard vending machines.
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• Smoking:
  Smoking is strictly not allowed on board. Some stations allow smoking on the platforms, but it is safe to assume that most central stations don’t. Always follow the lead of locals on board the trains or on the platforms.
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• Toilets:
  Toilets are available on board.
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• Charging:
  Some high-speed services do have charging ports at each seat, but it is safe to assume that most trains don’t have charging facilities on board.