This is the official site so you do need to register an email and the minimum of details at least do not feel obliged to give much away.
The Rule Books are basically the rules and procedures that everyone has to follow when dealing with incidents. These are a watered down version compared to the old style rules but a lot more understandable than before. So if you ever wondered what a driver does when he is stuck at a red signal now you can find out.
Also you might find the Traffic Circulars worth a quick read. These are issued weekly to all staff so have a selection of technical and less technical bits of information.