Have you considered that the anger is not "their actions are causing measurable negative consequence to me" but "their actions are outside my control"?
They did something that was not a part of our perfect little plan, and it simply irks us. We are so wrapped up in our own vision of how the world is, how the world will be for us, that we get angry when something happens counter to our vision. Yes, it is narcissism.
And that is okay. It is okay to recognize a problem and adapt to it or to regain control. When it is not okay is when our angry reaction is also negative.
To take your hypothetical situation: "If the inefficiency caused by a door stopper causes me to miss a train connection, is it really all about my ego, or is it about that person screwing up my entire travel?" I am sure all of us know somebody who is habitually late, and they have all kinds of excuses for it. So do people who are only sometimes late. This is just bad time management. The expectation that the world should operate perfectly in accordance with your plan is where I can claim it is about your ego. You are going to blame that one person for screwing up your travel? I like the pseudointellectual rationalization here, the excuse that it was the "inefficiency" of that other person that caused your problem. Maybe you should have gotten out of bed earlier. Maybe your affairs should have been in order before Go time. We like to place the blame on others rather than accept personal responsibility. That is just how important and infallible we are. Narcissism. Granted, that person's stopping behavior did have an impact, as did the speed of your walking, the amount of luggage you were carrying vs how much you worked out weeks before in order to more easily carry it, the stop lights on the way to the station, the time it took to get your ticket checked, and the line of other people boarding.
Again, please do not feel insulted if you fall in the narcissism category; we all do to varying degrees. Very common. My intent was to point it out as a huge contributing factor in order to balance things out a bit. The OP was trying to put the "ragers" in the clear, but as the saying goes, "It takes two to start a fight."