7 kinds of classes available on trains in China: hard seat, soft seat, first calss seat, seacond seat, hard sleeper, soft sleeper and deluxe soft sleeper.
Hard seat - the cheapest way to travel by train in China. Usually the hard seat carriage is crowded. In peak season you will find many people stand in the aisle. It's terrible to stay overnight in hard seat carriage, the seat is fixed and makes sleep very uncomfortable. It's a good option for a short distance rides. Hard seat is available on T, K, N, L, A and Number trains.
Hard seat on Shanghai - Lhasa train
Soft seat - soft seat is only available on a few trains. The carriage is clean and the seat is comfortable. It's nice for a shorter distance travel.
First class seat - first class seat is available on Z, D, C, G trains, the carriage has 4 seats per row, just similar as soft seat.
First class seat
Second calss seat - second class seat is available on Z, D, C, G trains, compared with first class seat, the carriage has 5 seat per row. But it is more comfortable then hard seat, it looks like the economic class of an airplane.
Second class seat
Hard sleeper - the carriage consists of cabins of six sleepers (upper, middle and lower), with three beds attached to the wall on either side. The cabin is open and has no door. So it's a little noisy and has no privacy. It's the most common way for foreigners and middle-class Chinese to travel long distances by train.
Soft sleeper - The cabin is clean and comfortable, has a sliding door and only four beds, also plenty of storage space provided. Soft sleeper beds have much more padding than hard sleepers.
Soft sleeper on a Z train
Deluxe soft sleeper - It looks like soft sleeper however the carbin only has 2 bunks with private toilet. Deluxe soft sleeper only available on few trains such as Beijing to Shanghai and Beijing to Xian. It's the highest class and the sleeper even features individual TV screen and power socket for laptop and mobile.
Deluxe soft sleeper carbin
Not all classes available on a train. Most long distance trains such as T, K, L, A, N and number have only 3 classes - hard seat, hard sleeper and soft sleeper. A C or G train may only have first class seat and seacond class seat. However A Z train may only have soft sleeper.