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Combat Engineers
Face-up ENG are not halved or thirded when attacking or overrunning across a river, canal or fort hexside. They also provide this benefit to as many land units they are stacked with as the ENG unit’s combat value. ENG attacking across both a river and a fort hexside, ignore only the fort hexside. The defender still has all other combat benefits if behind a fort hexside.

Engineers provide +1 to the land combat die roll (see 11.16.5) when attacking a 2 or 3 factory stack city. Defending engineers subtract 1 from the die roll when defending a 2 or 3 factory stack city. These benefits are in addition to the other benefits and can be used simultaneously (e.g. gaining both benefits when attacking across a river into a 2 factory city).

If an ENG provides any benefits in an attack, it always suffers the first loss (even before white print units attacking in winter).