I have spent the last day or 2 building a navigation box for Railcraft. It is now finished: http://ftbwiki.org/Template:Rc-nav
In the event that someone doesn't know what to do on the wiki and has a lot of experience with Railcraft, feel free to document some of it. I personally have little experience with Railcraft. All of the images, both grid and block/item have been uploaded as well.