I saw a simple but stupid question on a 'pre-hire' exam. "How high is a stack of washers if each washer is 5/16 inch thick" The obvious answer is 5/16" times X where X represents the number of washers in the stack. I was told that I was one of the few people who ever answered it correctly. Most just skipped it!!! You want an explaination of why there are so any train crashes on Norfolk Southern? One of the many exams you get during the 'gatekeeper' hiring process has far more questions than can be answered in the alotted time. They don't care how many you get wrong!!!! Only how many you get right!!!! The secret to the test is if you don't know the answer immediately skip it and go on. Answer as many as you can as fast as you can then go back and guess the rest!!!! Really!!! So, interpolating, if you don't know what the signal aspect means just run it and hit the next train head on as you'll probably get it right next time. These folks were the biggest bone heads I ever interviewed with, Well, except for maybe AirBorn in Lake City Pennsylvania. One of their interviewers was such an asshole I walked out of the interview but I did thank the interviewers who were serious and knowledgeable. It is a shame how one asswipe in management can make a work environment into a hell hole and kill employees spirits so they never rise to their real potential as a valued employee who contributes!! (P.S., Never tell Norfolk you worked for a short line railroad, that is an almost immediate "Skip this guy"!!! I know!!)