Sleeper buses are one of the main modes of transportation across the Tibetan Plateau. Inside, the bus is divided into 3 rows of bunk beds. The beds are narrow, short and very uncomfortable. Blankets are provided in the bus, but they are very dirty and are never washed. I have had to use blankets that have dried vomit and motor oil on them! In the winter months (October-May) the beds next to the window are very cold. Thick ice forms on the inside of the window. Since the beds are so narrow, one side of your body ends up next to the icy window. Most of the sleeper buses have heat, but there are still a few older ones that have no heat. Winter temperatures can easily drop to -25F (-32C) on the high plateau so getting a bus without heat is a nightmare. I once took a sleeper bus in the winter from Lhasa to Golmud that didn't have heat. Inside the bus it was easily 0F (-18C). I didn't sleep one minute on that bus ride. It was the worst experience of my life. Many men chain smoke in the buses adding to the misery.
Sleeper buses are only available on long distance routes across the Plateau such as Golmud to Lhasa, Xining to Lhasa, Lhasa to Chamdo, Chamdo to Chengdu, Xining to Jyekundo and Lhasa to Ngari. The buses have no bathrooms and only stop for bathroom breaks every 4 hours or so. You have to be careful on how much water you drink since the next stop could be several hours away. Most of the Tibetan Plateau is barren and uninhabited so the bathroom breaks are just out on the open plateau. Men will go to one side of the bus while women go to the other. The bus will also make a stop for lunch or dinner. The bus usualy stops in the middle of nowhere at some small Muslim noodle shop. Most people will bring small snacks along for the long ride.
Delays on sleeper buses are common. Flat tires, engine problems and heavy snow can all contribute to delays. Some breakdowns are short while others are for many hours. Most of the route is through some of the most remote areas on earth, so there are few mechanics along the way. The buses are usually manned by a driver and one or two assistants. These guys know how the buses work inside and out so they usually can get the bus running again. Occasionally heavy snow will shut the roads down for a period of time. This is not very common in southern Tibet, but it can happen on the northern Plateau. In February 2006 the buses between Yushu Tibet Autonomous Prefecture and Xining stopped running for over a week due to heavy snow.
Altitude sickness is a reality in Tibet. Most of the Plateau sits above 4500m (14,763ft) with passes over 5200m (17,060ft). Most Tibetans don't suffer from altitude sickness, but they do suffer from motion sickness. Many foreigners and Chinese who take sleeper buses in Tibet suffer from altitude sickness. It is not uncommon for people to throw up inside the bus or for the sides on the bus to be covered with throw up by the time it reaches its final destination.
I thought I would write a little about sleeper buses since a lot of my life seems to be on them. I frequently take the Lhasa-Golmud (18-22 hours) and Xining-Jyekundo (17-21 hours) buses. I never look forward to the long rides and am always glad when they are over.