Neal Hirsig pdf on the Rocket Steam Locomotive explains the formula for determining speed and rotation on pg20 - pg23 of the Animating The Rocket Steam Locomotive tutorial.
His website is no longer active but you can use the Archive.org link on the wayback machine website to still get to it.
Neals website for the tutorials is here,
His main site is located here,
http://web.archive.org/web/20170430020710/http://gryllus.net/Blender/3D.html
His videos are located on Vimeo,
https://vimeo.com/nhirsig/videos/sort:alphabetical/format:thumbnail
Although a little dated, its not hard to figure things out if you have a modest amount of blender knowledge. I highly recommend the tutorials on the Rocket Steam Locomotive. They are very fun to do and demonstrate almost every use of blender for modeling.