Storm wagons are a homebrew artillery piece made by resistance forces.

They are a truck with a servo controlled turret on the back. The turrets have home made rocket launchers either multiple rocket pods off helicopters, simple launch rails made of girders or a large amount of tubes containing crude rockets.

In small groups they are dangerous but are utterly devastating in larger units wiping out units through weight of fire than anything else.

The only down side is that they have no protection other than the armour bolted to them making them easy to kill.