There is a vague idea of a setting in my head, and I can not even remember whether I read a story with it, or was it a part of a game.
The only thing I remember is that there was a planet where nights (or days?) were so dangerous, that nobody could survive them even with stationary defenses. So instead, circular railroads were built around the planet, and people live in the trains always moving in the light.
The plot involved a civil war on one of the trains and one character making a motorized tram. He tried to charge through the night side of the planet, but found there another train of humans who believed that the opposite half of the day was deadly.
Google found me a couple of books where people migrate on trains regularly, but the key idea of this plot is that trains have almost no time to stop.