Full Steam Ahead

Universal Rule.
At the end of step 2 of the the Movement Phase Sequence (directly after Rallying Fleeing units), the Infernal Engine may engage its boiler.
If so, until the end of this Player Turn, the unit may not shoot and gains Random Movement (3D6), with the following exception: it cannot move into base contact with an enemy unit that was not within the Infernal Engine’s Front Arc before the initial Pivot.