A person who loves trains so much that it appears that he or she is sexually attracted to them. Locophiliacs often show their attraction to trains by taking numerous pictures of trains and posting them on social media sites.

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.