I almost feel like running a competition on this one to see what people come up with. I tried to work it out before reading the definition but I didn’t even come close!

Siderodromophilia is in fact the term used for people who find having sex in trains arousing, be it finding a quiet corner of a carriage, squeezing into the toilets to engage in a romp, or, the deluxe version (which also includes more overt exhibitionism), of booking a private cabin and going for it in front of the window as the train passes through populated areas or is pulling into a station, thus increasing the chances of being seen.

– The encyclopedia of Unusual Sex Practices, Brenda Love, 1992.