To sniff a line of cocaine, extacy, oxycontin or any powder drug.
"Ey, whats good man? You wanna bust a rail?"

"Nah, I don't fuck with that shit."
by VicBC January 27, 2012
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To go about snorting a powdered drug, usually cocaine but not limited to mdma, meth, and painkillers like vicodin or percadin.
Druggie: You down to bust some rails before the party?
Stoner: Sure, but I wanna smoke a bowl before we leave, too.
by TFS July 20, 2005
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