I would really recommend people that are interested in how coasters work to read through the articles that are posted in the "Coaster Basic" section on
www.coastersandmore.de . It's really a shame that they haven't been translated into English since they are written in such a way that they are easy to understand but still have all the info you will need to get how the things work, but Google translate (or other) usually gives a satisfactory (at least it's way better than translating from Japanese, etc.) result so that you will be able to read it.
I would also recommended the rest of the articles, especially those posted in the "Ride Insight" section, they have a lot of useful informations and feature a lot of great images...