Double Time: Order 4 or fewer foot units in a group (units in adjacent linked hexes that may span two sections). Each ordered unit (except war machines) may move two hexes and still engage in Close Combat. Warrior units may move 2 or 3 hexes, but must engage in Close Combat after doing so. Ordered units may not have Ranged Combat. If you do not have any foot units, order 1 unit of your choice. (2 cards)
NOTE: Light foot units do not gain any movement advantage when part of a Double Time order. The Double Time card symbolizes the final rush into Close Combat. Light foot units generally preferred to avoid Close Combat so they don’t have a move advantage. However, auxilia foot units gain a battle advantage when part of a Double Time order, as they can move 2 and still Close Combat.
On the '"Double Time" card can the group of 4 adjacent linked units span two sections?
Yes.
The focus of a Double Time card is that it allows Medium and Heavy infantry units that normally may only move 1 hex to move 2 hexes and still battle. Auxilia units that already move 2 hexes may now battle when moving 2 hexes. The action of moving 2 hexes and the unit still being able to battle is how Double Time takes precedence over the rule that normally these units can only move 1 hex and battle. A Double Time card does not allow units to ignore terrain battle or movement restrictions. (Richard Borg)