A few pointers for more people that are new to this:
When viewing the Dispatcher Display you will see green lines, red, lines, and blue lines. I believe blue means that a specific area between two signals is out of service due to a track authority. Red lines are actual trains or equipment that's large enough to complete the track circuit. (They can also be a bad circuit that is indicating something's there when it's really not. Green is how far a train can go or is "lined" as some say, before it hits a red signal. For instance: if you see a red line at West Seven mile on the NS New Castle District, and a green line to the west of it that ends at west Campbellstown, that likely means there is an approach at east Campbellstown, and a stop indication (red signal) at West Campbellstown.
If you see something goimg past a signal on the DP display and it doesn't appear to be lined anywhere but is still moving, that is usually a piece of equipment, a railgrinder, or something else that needs a track authority to work the line.
The snowflakes in winter time indicate that the switvh heaters are working.
This REALLY helps when you want to go eat but want to make sure you aren't going to miss anything if you leave BUT, if you are going some distance away, it helps to memorize how fast trains get to different points on the line so you can give yourself plenty of time to get back. In the old days, before ATCS, if you were hungry, you just had to risk it and use the HAPT. (The Hope And Pray Technique).
I know this thread is several months old but I thought some useful tips would be best posted here. Even I still don't know everything I would like to about ATCS. Someday I really need to sit down and read more in depth on it.