War engines in support of close combats
In contrast to regular units, you can use War Engine units to support other detachments that are in close combat.
To do this, your War Engine unit must not be engaged in combat itself, and must be within 15 cm of an enemy unit which is engaged in a combat (either in base contact, or lending support to the combat).
[TODO: It’d probably be best to define 'engaged' as a particular term in the Assault rules, and then use this term consistently in situations like this one.]
If you meet these conditions then, when you add up your Assault values in the combat, you may add a number equal to half the current Damage Capacity of your War Engine.
Ignore any Blast markers that your supporting War Engine detachment may have — do not count them towards modifiers in the close combat. And do not apply any Blast markers to this War Engine detachment if your side loses the combat.
Each War Engine unit can only support one close combat in each player’s Assault phase. [TODO: But presumably, a WE detachment can support multiple close combats if it has multiple WE units and they each support different combats?]