Stone throwers, bolt throwers and cannons are common to several armies, but in addition there are many strange war machines that are available only to specific armies. These are described in the Warhammer Armies books together with the special rules that apply to them. Examples include flame cannons which spout a sheet of flames, devastating multiple-barrelled organ cannons, and the deadly Skaven warpfire throwers.
Some of these unique war machines are so different that they have entirely new rules, but others are similar to the machines described above in that they consist of a weapon and its crew.
In general, when shooting at such machines, all hits are randomised between the machine and crew in the same way as hits on stone throwers, cannons and bolt throwers. Also generally speaking, when in close combat with such machines the same rules apply as to the crews of stone throwers, cannons and bolt throwers. Exceptions to these procedures are described together with the special rules for the weapons in the appropriate Warhammer Armies books.