A girl that is designated to give head and/or have sexual intercourse with any male that would like it. A different girl is usually designated every weekend.
Thomas - Yo George, who's the designated train runner this weekend?
George - I think Sarah O'Connell, she loves running train man.
George - I think Sarah O'Connell, she loves running train man.
by morgan 9875 April 21, 2008
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