This horn comes from the Trainz railroad simulator Ultimate Collection, where players drive detailed recreations of real British locomotives, including the Class 37 diesel workhorse long used for freight and passenger services. Because Trainz recordings aim to reproduce the real engine sounds rather than generic effects, clips like this one have been picked up by railway fans, model railway creators and simulator players for use outside the game. It remains popular because the Class 37 tone is distinctive, instantly signalling a classic British diesel and adding authenticity to train videos.