It's a travel diary by Paul Theroux of his year-long adventure across China by train in the 1980's. The book is named after one of the many trains he travels on, and provides a very in-depth view of the consequences of the changes brought about by the Cultural Revolution, as well as a very good insight into the lives and attitudes of the Chinese people. He writes well, with a highly intelligent and literate style, but also with wit, humour, warmth and emotion.
I highly recommend this book, I was unable to put it down and it provided me with a view into a world seldom seen or heard about from unbiased western eyes.