Ever wanted to build a railroad?

Have you ever wanted to build your own railroad, but had no idea how to do it? Well, you're in luck, because thanks to the internet, you can now get the design standards from various railroads, including Caltrain and theDenver RTD (which has standards for both Light Rail and Commuter Rail). It's pretty neat to see how it's actually done, although a little bit disturbing that, for example, Caltrain's choice of transition spirals is based on what AutoCAD supports, rather than on the copious research both in the US and elsewhere about what actually works best for reducing track forces and improving ride quality.