1) Anything moving at a rediculously fast or hard pace/ out of control

2)A gathering of many people all going somewhere at once, usually being overpacked in a car
1 (After seeing a very fast moving vehicle) "Damn, they're runnin a nig train!"

2 (After fitting the 8th person in a car that seats 6) "We're gonna have a pretty good nig train here."
by Caleb White September 3, 2007
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