I have been a bit frustrated by the "wishy washy" nature of the rules concerning Boxcars and Way Awful results so I have created/modified them for my game.
When you roll boxcars, meaning that both the plus and minus dice come up as 6s, something especially remarkable happens. Re-roll both dice. If another boxcars result comes up, ignore that, too, rolling until you get something other than boxcars. Boxcars wildly pump up successes and horribly worsen failures. The GM may describe this crazy event or ask you to do it, maybe adjusting your description to better fit her knowledge of the situation.
If you get a positive serve from a boxcars result and your action check succeeds, your opponent/s lose shots equal to your swerve. And if you kill your opponent in the attack and he can not, therefore, take shot loss you gain an immediate 0 shot cost extra attack.
If you get a negative swerve from a boxcars result and your action check fails, you lose shots equal to the absolute value your swerve. These "lost" shots can carry forward to the next sequence.
Sorcery is treated slightly differently in that when the negative swerve results in the failure of the action, you suffer Backlash but do not lose shots.
Example: You roll boxcars then roll again and get a 2 on the positive die and a 5 on the negative die, a swerve of -3, this results in your action check failing. This costs you another 3 shots in addition to the action shot cost.
Way Awful Failures
You get a Way Awful failure when you get a negative Action Result (almost invariably from one or more rerolled sixes on your minus die).*
You lose shots equal to the absolute value your negative action result.
Sorcery is treated differently on a Way Awful failure, you suffer Backlash but do not lose shots.
Example: After rolling a string of negative sixes for your swerve and adding your skill you end up with a total of -5, a Way Awful result! This costs you another 5 shots in addition to the action shot cost.
* Please note this is now the ONLY way you can get a Way Awful result.
** Ignore the Gun Malfunction rules for Way Awful results, this is replaced by these "new" rules above
Now these shot losses may exceed the "normal" penalty for Boxcars and Way Awful results but I think it gives degrees of failure or success. Just how wildly your success was pumped up and how horribly worst your failure was