Gudok poezda is simply the Russian phrase for a train horn, and this clip is a straightforward recording of that everyday railway sound rather than a line from a film or show. Because the horn is loud, clear and universally understood, it has become a handy stock effect for Russian-speaking creators and meme editors, who search for it by its Russian name as well as in English. It is reused in travel videos, comedy edits and reaction clips whenever a creator needs an instant signal of arrival, departure or something large approaching.