Top definition
when you snort a rail of cocaine and then snort a rail of crystal meth immediately afterwards (or vice versa). A speed rail can also be when you chop up the cocaine and crystal meth at the same time and mix them together to create one fat rail that is comprised of both cocaine and crystal.
I think Felch is going to have a heart attack, he just took 5 speed rails
by Isak August 16, 2004
Happy St. Patties Day!