I am thinking of setting up a Server for testing/training purposes. Will make Primoz happy at least... He needs to practice managing 2000 trucks.

Most of the resources you will need to learn how to play have been mentioned in this thread already, but I am happy to answer any questions. Signalling is one of the harder areas to get right.
Something I must try is single line with the ability for trains to follow.
Key: > Path Signal Type, '>' indicates direction of Front of Signal Face - Train can wait in front of signals, they cannot wait behind them
CODE
3< 9<
------------------- ----------------------
/ 1> 4< \ 6< / 7> 10< \
-------------------------------------------------------------------------------------
2> 5> 8>
Note: Signals 5 and 6 face each other, they are not the block signals that face opposite of each other.
Lets say you have two trains moving from left to right, both in the loop on the left waiting at Signal 3 and 4. Furthermore, there is a train heading right to left waiting at Signal 7. As the first train leaves the loop, it will reserve a path from Signal 4 to 10. As it moves past Signal 6, the path comes clear for the train sitting at Signal 3.
This allows it to follow the first train on a single line section.
In other words, you can build long single line sections like this:
CODE
2< 4< 6< 8<
----------------------------------------------------------------------------------
1> 3> 5> 7>
And you can be sure that two trains will never enter that same single-line section from both ends and end up facing each. Further more, it allows multiple trains to move in the same direction. Essentially priority is given to the direction that is most busy, but it also means trains trying to go in the opposite direction will wait for a while.
Crikey, typed more than I thought I was going to.