So apparently Train Guys (guys who like trains) are disparagingly referred to as “Foamers” (as in they foam at the mouth when they see trains) and are filtered out of the interview process if the company notices any excitement. Sadly, we live in such a dystopia that companies turn people away for being too interested.
Source: Ante D. Luvian
I think the name arose from the blank, zombie like expression, stance, and generally extra close to the rail location from which to fawn over the trains.
I imagine it to be a strange and possibly disturbing sight. Especially the 1st coulpe tmes