After police pursuits, my 2nd guilty pleasure on YouTube is watching train videos. I don’t consider myself a real railfan, but I do enjoy wasting my time in front of actual trains and train videos like this one on YouTube.
Anyway, in my experience of watching lots and lots and lots and lots and lots of videos of trains, I’ve come to learn that when a train goes in to Emergency, it means that the train is coming to a complete stop as quickly as possible in order to avoid derailment, collision, or another type of accident. Sometimes however, Emergency occurs even when there is no emergency present and usually you can hear it happening when the train releases a loud compressed air sound. You’ll know what I mean near the end of the video above.