Head-end View wrote:And to clarify, no way that signals in both directions could be green at the same time (except for a malfunction) causing a "false clear". I'm sure the "system" cannot do that. If for example, the dispatcher cleared the northbound signals for the next train, the southbound signals would be red automatically.
For controlled signals, you're exactly right, but for intermediate signals, that's not necessarily true. The third picture in this post from Jersey Mike's excellent signals blog illustrates this concept well:
http://position-light.blogspot.com/2014 ... shots.html" onclick="window.open(this.href);return false; It makes sense, that way the only control logic is to the controlled signals at each end of a stretch of track, the signals just behave based on what the "next" indication is rather than what the controlled signals show.
I have seen this kind of thing in real life myself. Signals between control points will show clear in both directions until a train approaches close enough to trigger the sequence of stop->approach->clear or whatever the proper sequence is. I'm sure it sounds dangerous, but if you think about it, a train can't approach except from a controlled signal, and even if a giant stork happened to drop a bouncing baby train directly on the tracks without passing a controlled signal, it would still be fine because the signals surrounding that block would drop to stop, the signals around those would drop to their respective aspects (approach, then maybe advance approach if necessary or approach medium if you're CSX), and the dispatcher would grumble obscenities and go stork hunting.