Sometimes, in OpenTTD, it can be difficult to see which direction a train is facing. And sometimes, a train might be going down a track the wrong way (why? I have no idea). So you try to click on the "reverse train" button. And miss. And click on the "ignore signal" button instead. And there's a passenger train (going the right way) just on the other side of that signal. And there isn't enough time for you to stop the train. And you kill 208 people. At this point, there's nothing left to do but replace those two trains and wipe the tears from your face/blood from your hands with your massive pile of money.