1) Dozen 2) Freight carriers 3) Twelve 1) Sixes 2) Twelve 
[slang] Boxcars (also: `Midnight`) is the outcome of rolling the dice in a game of craps and getting a 6 on each die. The pair of 6 pips resembles a pair of boxcars on a freight train. In modern parlance, it refers to such a roll in any game involving 6 sided dice which are marked with pips. The probability of this roll is 1 in 36, or about...
[n] - (usually plural) when two dice are thrown and both come up showing six spots the result is called `boxcars`
noun (usually plural) when two dice are thrown and both come up showing six spots the result is called `boxcars`