Pretty much what the title says. Kinda like minecarts

 Support :D

Brilliant idea Shane! 

I like it!

as arc or soapsud would say: Format??? xD

There's really no need for the format here because it wouldnt add anything to the suggestion, the title pretty much says it all

Suggestion:

Any projectiles that pass through the doors could retain relative speed and direction when passing through the doors.

As for a format, there could be one. Though I wouldn't think it's necessarily needed here