A number of people have asked for recommendations for guidebooks. Both of the following books are first rate, and will make your trip much more enjoyable.
The Trans-Siberian Rail Guide The guide book that I used on my trip is out of print, but I have a copy of and have read this guide, and it's very good. It's the most up to date guidebook you're going to find for the TSRR.
Russia By Rail Written by Russian Rail veteran Athol Yates, this book covers not only the Trans-Siberian, but also other lines in the former Soviet Union. I haven't reviewed it personally, but I am familiar with Yate's work and he does a good job. I would consider this one if you taking trips in Russia other than the Trans-Siberian
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