Think of them like separators, so ==1===!=======2=========!=====3======
where = is track ! is a signal and the numbers are the section of track
As long as the train is in section 1, it is "locked" to any other trains. As soon as it enters section 2, that section is locked and now the second train can enter section 1.
Just remember to always put up signals in pairs so you have an "on" and an "off" and everything will work pretty well. --- Welcome to GameFAQs, the largest 90s styled forum with only a few modern features that nobody asked for. ~bangvang