What is Brain Train?
1.
It's your train of thought, which all goes to naught if what you end up with isn't what you sought.
"Shit yo, your brain train just derailed! That shit ain't germane to ANY topic" - said to someone whose conversation went from sleeping bags to whether it would hurt to be slapped in the face with a dick
See
2.
A group of attractive females travelling all places together, generally with one less attractive one to further their own appaearances; see Brain, sloth, and sloth caboose.
"oh man, looks like a brain train is rolling into our station."
