A term railroad employees use to describe a railroad enthusiast / railfan and the railfan community at large. Most often used disparagingly.
(Engineer to conductor aboard a freight train)

"Man, we got some foamers ahead taking pictures...they need to just get a life and find something to do besides hang around the tracks all day."
by Aeromoe February 28, 2008
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The rail fan's equivalent of weeaboo, derived from foaming at the mouth at the sight of some trains
Foamer: zOmG tHaT's A uNiOn PaCiFiC DD40XX
Honest rail fan: fuckin' foamers...
by CaptainOppai November 13, 2021
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Someone who loses their mind over any train, usually a rail fanner or train buff. Most of the time they show no regard for their surroundings or to anyone really.
OMG, that foamer is so annoying! He's always yelling at the train station when a train passes by and throwing garbage on the tracks! GO LOOSE YOUR DICK SOMEWHERE ELSE
by EL SEXO GRATIS October 4, 2023
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A foamer is a rail fan, most likely someone who has just gotten into the hobby, who foams at the mouth when they see a train.
"The foamer's mouth foamed at the UP Big Boy passing by."
by a idiot lol September 4, 2019
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The type of n00b who would use derogatory rail slang like SCAXliner or Amtrash, complains about the tuning of train horns, tends to endanger his or other's lives for a good photo, and angers railroad crews through his actions.

Also tends to spam youtube haters' channels, and tend to harrangue people via internet, cell phone, etc.
J: OHMYGAWSH AWESOME K5LA ON THIS TRAIN!

G: Dude calm down, don't be such a foamer.

J: OHMAIGAWD SHAVE AND A HAIRCUT PLZ!?
*cuts in front of parked train*
MUST HAEV GUD GOING AWAY SHOT!!!!1111
by AmtrakFan454 February 11, 2011
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A sacrilegious dumbass who simps over trains, more often than not, over a specific railroad or locomotive. A foamer is often ridiculously stupid and is really hard to argue with because they are so naive with the science and art behind railroading and only care about the trains they set eyes on.
Rail Enthusiast: "Damn that foamer foaming hard for some normal NS SD70ACe with the number 1111."
Another Rail Enthusiast: "Don't worry, I see foamers flipping out over an awful looking Caltrain f40ph with a shitty horn, and thats a normal for me."
by UnknownUser225 November 10, 2021
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(n). A stereotypical fan who loves to make bias and make fake facts of said hobby. Generally, this term is used by anyone who’s overly obsessed with commonly seen trains. This term is also generally accepted in the bus and aviation community.
Oh my god, that kid really said that bus has a Cummins, but actually has a Detroit Diesel. That kid is a foamer
by 901.lax January 6, 2020
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