A person who can sucessfully identify obscure music a DJ plays. A hardcore trainspotter can take it a step further and identify the source of obscure samples.

A polite term for shoving a lubricated probe into the Earth's hole to release gas.

someone who obsessively collects bits of useless information

see also: nerd.

The term 'trainspotter' stems from exactly that......he who spots trains. A strange affliction. These are characteristically 30 - 40 year old men who still live with their mothers and quite possibly indulge in dubious sexual practices involving them. Gathering on station platforms in all weathers and wearing old anoraks and bobbly hats, they note the make, model and characteristics of each train that passes. Thus 'trainspotter' has come to mean any obsessed character who insists on talking about nothing but their chosen specialist subject. In my experience, the 'trainspotter' or 'pothouse' almost always manifests itself at the aftershow hospitality.

Somebody who mainlines heroin.

–noun
1. a person who hovers around a performing djs'turntables and attempts to identify his tracks by label, artist, and or song title, in an attempt to search out and perform the same set. Trainspotter can also be used as a verb, as in "I caught that douche bag trainspotting muh set!"

Person who spots trains for a hobby. Usually the preserve of sad anoraks.