Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Lots of momentum in this book.

I read this book in 4 nights. It's perfect for people who are interested in finding out more about the building of the transcontinental railroad but who don't want all of the nitty gritty. It really reads like an adventure story in so many ways. I don't give it 5 stars because there is some strange repetition of quotes and stories throughout the book, especially towards the end where it looks like the author and editor ran out of steam. I kept flipping back trying to find where I had read that particular story before. But I truly enjoyed this book!!